RPM's dipping

[megan_mf]

I bought my 2008 Chevy Aveo used around this time last year and about four months after I bought the car the alternator needed to be replaced. I don't think this problem is occuring with any relation to the alternator, but I noticed in the morning when I start up the car the engine will rev like it normally does when you turn it on but once the needle drops down it occasionally drops down to 200-400 rpms. This also occurs when I break coming up to a stop sign or red light, when I apply the break and come close to a stop the rpms will drop to 200-400. I am curious if anyone has had similar problems and what might cause this?

[khan4rtist]

Ive had this problem on top of other problems at the same time. For me, it was a torn hose that goes from the MAP sensor to the intake manifold. Check that vacuum line for leaks and tears; if you find a tear then replace the hose. This fixed the issue for me. If that does not work you may want to try replacing the MAP sensor and/or O2 sensors. I'm not a mechanic but this is what I would do. Are you getting a check engine light?

[megan_mf]

I haven't taken it in yet, but I'll probably do it soon. No there is no check engine light although a week ago the engine light came on and I got a code reader from checkers auto parts and it read code p2130 throttle position sensor, it only last like two days though and shut off.

[jayman]

just try cleaning out the throttle body with some brake cleaner and see if that helps.

[khan4rtist]

Ahhh P2130. Your TP sensor may be bad. I had this code when my engine sucked in water. I'm sure your car is drive by wire like mine so you wont be able to replace just the sensor. You will need to replace the entire throttle body because the sensor is built into it.

[megan_mf]

Yeah I read about that but the code has only came on once, so I'll have chevy look at it, but I've also been having a problem with the first cylinder misfiring occasionally. I read on ehow about replacing valves but I'm not sure if that's the case. And could you explain a little bit more about cleaning the throttle body? Where is this located?

[MrGrumpy89]

Yeah I read about that but the code has only came on once, so I'll have chevy look at it, but I've also been having a problem with the first cylinder misfiring occasionally. I read on ehow about replacing valves but I'm not sure if that's the case. And could you explain a little bit more about cleaning the throttle body? Where is this located?

for your mis-fire one thing I would check is your spark plugs. Last winter I was getting mis-fires and jerky when I accelerate. The gap on mine was about .060 in. Check the gap I believe it should be like .045 in. cause the stock plugs are not the best. They are rated at 25,000 miles. I put Autolite double platnim in my are and the problem was solved. The double platnum plugs are also rated at 100,00 miles. and for about 4.50 a piece not too bad, less than 20 bucks for 4.