Need Help dont know what to do, engine not having power.

Ok guys, I'm still pretty new to the forums here, but I have an 07 Aveo, it's an automatic 1.6 liter DOHC. A couple of days ago i was running the A/C outside of my house to cool off the car. The car was running for about 10 minutes. I then drove it and it sputtered out and stalled on me. At first I couldn't get the car to start again and turn over, I waited about 5 minutes and it started but the only way to keep it on was for me to constantly press on the gas. I turned it off and waited again, I then started it and it stayed running but was sputtering really bad when I tried to drive it I was losing power, and couldn't get it above 30 MPH and that was when I was flooring the gas pedal.

I took it to Advance Auto to test some codes and I had it came back with 13 codes, they were:
P0420 - MOD II Catalyst below threshold
P0496 - EVAP high purge flow
P0455 - EVAP Leak
P0106 - Manifold Absolute sensor
P0300 - Random Misfires
P0451 - EVAP Preset switch
P0302 - Cylinder 2 misfire
P0303 - Cylinder 3 misfire
P0420 - Catalyst Threshold sensor

Some of these repeated which accounted for the 13. The technician at Advance auto told me that it sounded to him like it was a valve cover gasket leak, due to also having oil sprayed everywhere and down into my spark plugs and all over my wires.

We replaced the gaskets, wires and spark plugs, and the car ran a little better, however I was still having to floor it to get anywhere, but was able to get it to 40 MPH. We took it back to Advance auto today, and reset the codes.We let the car run for a little bit and then revved the engine, there was a little sputtering but not like before, then the check engine light came back on. We checked the codes again and there were only 5 this time.

Cylinders 1-4 misfires, and a Multiple cylinder misfire, as well as a Random unknown misfire detected.

The technician recommended this time that the catalytic converter be replaced, as well as the coil. We could not order a catalytic converter so he recommended a stock Magnaflow converter, he said it was for a higher horsepower engine but would work just fine, the problem was getting it to fit. We also noticed there was a crack in the intake hose which runs from the air filter case to the intake manifold, but we couldn't find a replacement for that either. While we cleaned and replaced everything last night, we also cleaned the MAF with MAF cleaner recommended by Advance auto. I just don't know what to do, or if the additional work I put in is worth it. I cannot find a catalytic converter, and I don't even know if thats the issue. I live in the Kansas City, MO area, its an 07 Aveo with 30,000 miles on it and i still owe $2700.

Also in additions two years ago I had my transmission go out, and the dealership replaced it along with the catalytic converter and head gaskets, as they said it needed it and it was all still under the powertrain warranty, so it was at no cost to me.


Any help would greatly be appreciated, Thank You.

-Bearski

You cleaned the maf based on the guys recommendation at autozone?

your have has a map and IAT sensor, not a maf. What did you clean? The tear in the intake can be detrimental if it is on the engine side of those two sensors. especially at throttle. Your car would not be giving it enough gas based on how much is being read by the sensors.


Second, if you still have misfire codes, and replaced the CAT once. I would agree you may need the coil. Try testing your wires, and routing again, however. start the car and mist water over everything while it is running, use a spray bottle. Do the wires first and then the coil pack, if it is a arcing coil pack, then you will see it short out (sparks) and the idle will change. DO NOT TOUCH THE CAR WHILE DOING THIS, 40000 + volts hurts a little.

The cat on a 07, should be under warranty, unless you have over 100k miles? If it needs changed, then it should be free. If ou have the same o2 that was in the bad cat, it might be a bad o2. But a secondary o2 will cause a light, but not necessarily a running issue.

run an oem replacement cat if you are buying your own, probably $370 on ebay.

Yeah, that's what he told me to do, he pointed it out and then told my to buy this cleaner and spray it down with due to it maybe sucking oil into the sensor.

Yeah, I must apologize when I said 30,000 miles I meant 130,000 miles. I haven't replaced the catalytic converter yet, as i've not been able to find one here locally that will fit my car, I haven't tried online yet either. I just dont want to have to expensive parts if there may not be anything wrong with them. When I did the sytem diagnostic at Advanced auto parts it said that my Catalyst sensors were ok, however i'm still not getting power when I hit the gas pedal and it is still sputtering and misfiring. In addtion two years ago, I had my transmission go out on me and the dealership replaced it along with my head gaskets and catalytic converter, as they said it all needed to be replaced, but at the time this was all still under my powertrain warranty which has since expired.

I mean its running a little better compared to two days ago, but money is the issue here, ive already spent about $250 into it the past two days. The technician, at Advance auto, really thinks its the coil, but the car starts up fine, he also thinks its the air intake hose, but I also cannot find one of those locally.

Thanks Petrified.Rabbit

-Bearski

i would replace the coil, and if you wanted to you can take off the exhaust manifold and look at the cat itself, as far as the intake hose you can take the whole thing off and it wont hurt anything short term, so i doubt that's the problem

Thanks jayman,

Yeah I replaced the air intake hose today, an it ran a little better, but it still had a loss of power and it still sputters and vibrates like crazy. I mean I have to floor the gas an it barely goes anywhere and then it takes a while to build up RPMs and then it still had a problem going over 50 MPH, and if I'm on an incline forget about it, it will barely run. It's still setting of random and multiple misfire codes, and I have to do this thing where I floor the gas and build up RPMs then let off the gas before it changes gears and gets a little Lowe, and it's an automatic. It also idles hard with the sputtering and vibration, I'm hopefully going to look at getting a could and converter tomorrow, but someone else told me today it was a timing belt issue. But today when I did a systems check at advance auto to check the codes, it ran a diagnostic and said the CAT system monitor check couldn't be completed , as well as the EVAP Systems check. So I have no idea what that means.

how many miles are on it? usually if its a timing belt issue it wont start

It sounds like your down to solving three problems?

The evap system wouldnt cause a running issue. unless it was a huge vacuum leak which really would be kind of the opposite of the problem you describe.

The cat system issue, aside from the code could cause an issue just like this. A clogged cat will kill you rpms higher volume air flow.

The coil will do it too. Did you mist the coil, plugs and wires like i suggested?

The timing belt, while due at 120k might be the problem, but didnt i suggest a compression test?

Here are the wrong ways to test/fix it to get the right answers:

Pull the primary o2 sensor out of the manifold. leave it plugged in, but tucked safely away, or wire tie it right beside the o2 hole. Start and drive the car (you going to blow exhaust right in front of you, set a light, and have new running issues, so this is really for a short test drive). If not having the o2 in the manifold fixes the acceleration, then your cat is clogged. You will need to replace it.

The coil. Mist it with water while it is running, start with the ends of the spark plug wires. If its shorting out 99% of the time it will throw sparks, change idle when you hit the worn/bad spot. Whatever arcs will need replaced. If you dont have the money to replace the coil, and it arcs, take it off and fill the cracks and coat the entire thing in ultra black. I have done this with success, but its not going to fix an internal arcing across plates.

The evap system is hard to diagnose, as it is only supposed to work while moving. However, both those codes could be the gas cap, check it for leaks, check the o ring etc.

The timing belt, you check the timing marks.. make sure they are on, and give the car a compression test to verify the valve are ok.

Hey Jayman there are 130,000 miles on it.

And thanks petrified.rabbit, no I didn't get the chance to test any of that just yet, but I will do it today. I'll post later today or tomorrow to let you guys know what I find.

Thank you for all of your help!

Okay guys,

Today I performed the test petrified.rabbit recommended for the CAT, when I removed the O2 sensor and fired up the engine it at first sputtered but then it started to sound like I was driving a motorcycle, which I suppose is customary for when the exhaust is coming out of the front. Anyway, I did this and my car stopped vibrating really bad and the engine seemed to run smoother, however I still had a problem with getting power. The car ran better and I had better power, but it still had to build up the power and RPM's, but it wasn't as bad as it was before.

Im a little nervous to perform the spraying of water, as I have been electrocuted before pretty bad, and its just a fear I have of it happening again lol. But since the car ran better with the exhaust coming out of the O2 sensor port, it's looking like it's a CAT problem right, I mean the car doesn't have a problem starting, just with sputtering and getting power. How would a Coil affect those problems?

Thanks guys I really appreciate all your help, I know it may be annoying that I ask all these questions, and repeated questions, it's just my first time dealing with any of this, so I want to be sure i'm doing everything right and do not mess anything up worse.

Thanks again.

im pretty sure you can take the cat off the manifold itself and see if that helps, but it will just be very very loud!

keep in mind the exhaust is almost 2" and the o2 sensor hole is barely a 1/2"

but if it ran better, aside from the issues of no o2 sensor, then you are highly likely to have a clogged cat.


The coil if it is bad, will absolutely kill power. If you spray the stuff with a spray bottle, dont lean on the car etc. you will not get shocked. It will arc to the engine head (path of least resistance). Just keep your distance and do it at night, so yo can see the light show, versus looking for it.

Yeah, with the O2 sensor off I thought that I would gget my power back, but it still has a loss of peer and I have to floor it to build up RPMs, but it was running a little better, I put the O2 sensor back on and drive it to work which is about 15 miles away and I had to have the gas pedal floored the entire way on the highway, and it went through a half tank of gas. So yeahbim thinking it may just be the CAT and O2 sensor needing replaced. I was able to get it up to 70 and the turn on the cruise control, but anytime I came across an incline it starting losing speed and power an the engine went into high RPM mode. What do you guys think, CAT and O2 sensor right, I'm talking with an exhaust shop tomorrow.

Thanks guys.

Just curious, how many catalytic converters are there on a chevy aveo. I just finished talking with n exhaust shop and they were telling me that there are 2 converters on it. Theres the manifold converter and they said there is one right behind and below that one. I looked and could only find the manifold converter. Has anyone heard of there being two catalytic converters on a 07 chevy aveo sedan?

nope, just one cat

my 09 has a post cat, its about under the shifter.

My 08 has 2 cats on it, IMO i would say its the coil. Mist water over it and that will tell you. If the coil is bad, that would cause the cat to go bad. ( happened to an 02 ford tarus, coil went bad and took all 3 cats with it. ) Why fix one thing that is an issue and come back to the original issue that caused the issue in the first place? To sum it up, check your coil... Mist it with water. Just stand back you will not get shocked...

I took the CAT off of the manifold today, and yes it was very loud! However it didn't run much better, it still had no power to it, and when I floored the gas pedal it still had to build up RPM's and it barely had any power, so to me it doesn't seem like it's the CAT. Any other suggestions? Could it be a thrown rod or something? I know you guys suggested the coil, but if it was the coil wouldn't it have problems starting? It starts up no problem.

Also, when I took of the Manifold CAT, there was nothing inside of it. It was smooth as can be on the inside and I could see right through it.

stop thinking and check the coil already

running straight manifold will not give ideal running either, but you should have seen some improvement if the cat was clogged.

if it ran better with the o2 pulled it could be that. do you have a code?

to go along with rabbit check your plugs as well the valve cover gasket is bad in out cars and it seeps oil down into the combustion cmber it could also foil your plugs.

when my coil went bad it still started up fine every time

My coil pack was replaced in January. A back flow test by mechanic showed excessive pressure and he thinks the cat is clogged, any idea where he would have taken this reading from? He said it took 10 mins and didn't charge me, should he have taken the reading from the 1st oxygen sensor hole, the 2nd oxygen sensor hole (the one after the cat), or is there a valve?

I'm going to try removing the 1st 02 sensor again (I still have the manifold off), keeping it plugged in, and seeing if the car accelerates differently/better. Right now, I can't get over 2500 rpms, and the top speed is 60 mph.

If it's the catalytic converter, since I have a 2008 with 43k miles, its replacement, parts and labor should all be covered under the Federal Emissions Warranty 80k/8 years: http://www.epa.gov/obd/pubs/420f09048.pdf.

I assume my mechanic couldn't do this work and it would have to be done my a certified GM tech?

Update:

The backflow test was done from the 1st 02 Sensor Hole (before cat), as expected.

With the 1st 02 Sensor removed but hooked up, the car was understandably louder, but ran much better. In fact, if not for the noise, it was hard to tell anything was wrong. I was able to get 2nd gear well past 2500 rpm, upwards of 4k, and in 5th gear, I got past 60 mph, up to 70 mph with no issues.

The codes that resulted from this test were P0131 and P2187.

Thanks for that tip!

its tough when no one replies, but congrats on what sound like you fixed your car.

Thanks rabbit, I have a 1 PM appt at a local dealer. The tech looked up my VIN and confirmed that if it's the cat, diagnosis/labor/parts will be covered by the Emissions Warranty. I will follow up after that.

Hello ranjmaz

Feel free to keep me posted on your dealer visit and how your Aveo is running. Also remember that if you have any questions or need any assistance to let me know by private message.

Jackie
Chevrolet Customer Care

My car has been fixed free of charge under the Federal Emissions Warranty (8yrs/80k miles) and is running great. Many thanks to Petrified Rabbit, Jackie and the fine folks at Alma GMC, in Michigan. I am going to post a new thread under maintenance detailing my ordeal and this Warranty fix, which doesn't seem to be well known and perhaps should be.

Thanks,

RanjMaz