Engine Light and Hold light flashing

So I have read another post on this before and see that there is probably a misfire, either from a bad coil pack, wire or spark plug.

But the engine doesn't seem to be having a misfire (or it doesn't happen when idle).

Some background on this car, its a 2005 and the guy I bought it from had the car sitting for about one year. He had replaced the timing belt, head gasket and a couple of other things.

I have cleared the codes by unplugging the battery for 15 minutes and this car does throw the lights up again right away. I've also noticed that 3 of the 4 plug wires have been replaced with blue ngk wires, while the 4th looks original.

I just went out on my lunch hour and bought an obd2 reader, going to see what specific codes are coming up.

Was wondering if there is anything I am missing from this troubleshooting list. Thanks!

Compression and/or leak down test. With the history you posted, IMO you should do one or both of those first, in order to confirm what shape the engine is internally.

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Originally Posted by avguy

Compression and/or leak down test. With the history you posted, IMO you should do one or both of those first, in order to confirm what shape the engine is internally.

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I guess I should go out and buy a compression tester. I will wait to see what the codes are first, but I imagine its going to be p03xx

So I got an OBD2 reader. Code is p0300 just like I thought. Going to be replacing the first cyclinder spark plug as when I pulled all the plugs out that seemed to be the one that looked worse for wear, there was build up of oil I'm guessing because it wasn't firing.

I did the misting of the coil and wires trick, and didn't get any arcing just to check that they were not the issue. Although I know thats not a for sure way of knowing. I just didn't feel comfortable with pulling the spark plug wires off the coil while it was running.

The spark plug wires have been replaced. I talked to the guy I bought it off who is a mechanic and he believes there is a vacuum leak. But the only code I ever got was p0300 and my engine light and hold light still are flashing.

Any ideas?

So I have done everything, compression tests, looked for vacuum leaks and replaced coil pack, sparks plugs and spark plug wires. Still have this problem and I am stuck. Currently just tricking the computer so it will shift into 4th when I need it. (I have a obd2 reader to clear the p0300 code plugged in as I drive)

the p0300 code is just a general misfire code. you do not have a p0301, p0302, p0303 or p0304 too, do you?
That would help narrow it down if you did.

Just a few possibilities...

Are the plug wires on the correct way? i know that sounds stupid but it is a "traditional" waste spark and can run backwards..
but also be considered a misfire. Also if you have the wrong plugs in, it could also trigger this issue. any power loss issues?

A big indicator that it might still the coil pack is the hold light.. But it could be a ground issue as well. Check your transmission/engine ground strap to make sure they were hooked up with the head gasket change. If bought a coil pack, its hard to say try another. But the signal for the hold light I think you would get a code for too do you have one?

Another way to for the engine to miss is no fuel, if the car sat a while like you said you might need to clean out the injectors.
have you done your other maintenance like air filter, oil, etc on time? Fuel filter?

Just the p0300 code, which is stored and pending when I check the codes, so its on going as the car runs.

I'm pretty sure the wires are on correctly, considering the lengths. I didn't reference a diagram or anything though.

Which are the correct plugs, I didn't replace the plugs myself, they were done at the time of purchase from the guy who sold me the car.

I don't have any power loss, it accelerates in the lower gears fairly easy.

With checking the ground, how should I go about that? Im not sure where its located to be honest.

I haven't changed air filter, oil, or a fuel filter. But looking at the air filter it is a little dirty. I should do these things then too.

I appreciate your detailed response!

So interesting development! I have had the lights not flashing for about a day. But they came back on when my girlfriend filled the car with gas. I made sure the cap was back on properly. But it seems this issue is arising when the car is refilled with gas.

The lights consistently do not come on when the car is around 1/8 of a tank of gas or less. So I going to try and clean out the fuel pump and filter and see what that does.