Ok here is a sequence of events for the problem, it started with this:


This just started about a week or so ago and it does not do this all the time.

The problem seems to happen when the air temperature is at or below 40 degrees. I start the car, and the best i can describe it, is it sounds like a pulsating miss. If you give it some rpm it, just sounds awful. But, as you let it idle, for a couple minutes, it smoothes out and eventually runs normally.
Turn it off, and start it again, nothing. Runs fine.

What gives?



After this i was told to check various sensors and this is what happened next:

ok heres what ive done.

Today i thought i would check the maf, so after the car was warmed up, i unplugged the maf, nothing happened. I went for a drive, drove exactly the same, so im thinking ive got a bad maf. I go to napa, get a replacement maf, install it, and now when i unplug it it almost stalls completley then resumes idle (cant really tell if its any worse, the car is pretty lopey when running normally). The car ran great on the way back to the house.

i changed my oil, and now the car runs like complete garbage. It runs what smells like VERY rich, and when you start it when its warm, it idles high (about 1500) for about 20 seconds before it comes back down. The idle isnt as smooth as it was, but it was never that smooth anyway due to the cam.

The only thing i can think of that might of chaged is this: The passenger side o2 sensor is in an inconvient place (due to my lack of test fitment when installed). When the car is jacked up the lower a arm comes down into contact with the very end of the sensor. My sensor on that side is bent at the end, and the little plastic ring that goes around the wires is coming off. So my thoughts are this sensor might be bad. But i am unsure if a bad o2 would cause these problems.

The car has about 1/2 the power it normally has. Keep in mind the car does want to fall on its face when the maf is unpluged.

I cant tell you about any codes as i dont have a scanner.


Can anybody help me?

 

If it idles bad when in open loop, then gets better as it enters closed loop i would say o2's are fine. I would try to datalog the car and see what info you can get off of that.. any exhaust leaks or intake leaks after the maf??

 

No leaks. It not nessiearily running better in closed loop since the new problem. It's all the time. I did forget to mention the porcelain on one of the spark plugs is half off so I will be replacing that.

The car does not throw codes while running. My little sea light does not come on.

 

Fixed plug. Still runs bad all the time closed loop, open loop, whatever. Unplugged maf still runs like crap. No codes. I'm going to check for wires and replace the o2 since that's the only thing that could have gotten damaged from my changing the oil. Any other ideas please chime in.

 

Ahhh no go. Bad maf maybe?

 

Well it's running worse now than ever. I got my old maf back and doesn't help. I replaced the o2. Nothing. I'm thinking maybe I fouled my plugs so I'm trying that next. Still no codes.

It stumbles all the time and tries to stall every now and then.

 

Well my plugs aren't the problem

 

have you checked the temp sensor in the water pump?

 

I thought about it, but I figured it out anyway. Let this be a lesson to always check the simple things first. I had two plug wires crossed.

 

o ouch...well glad you got it figured out