Fueling & Injection - HELP! Car is running awful!!

Guess it's a good thing I didn't go out tonight. My car is running awful. I replaced the stock MAF 2 days ago and car ran fine. I took off Hypertech power programming this morning. While washing the car, I popped the hood and cleaned under there too with the hose. I went to start the car and it only made clicking sounds. I figured I killed the battery while listening to the radio and screwing around. Neighbor gave me a jump. Left for the gym. Car started running funny. Like it was running on 4 cylinders. Stalled on me a couple times. I figured it probably was just from getting things under the hood wet and it would go away. Well after about 10 mins of driving it seemed like it did. I get to my parents house and let my dad take the car for a spin. It started running like shit again. I had just driven the car 30 miles now so that should have been far enough I would think. Again after about 5-10 mins it was fine. Well this has been the situation all day. Everytime I turn the car off - even for only 5 mins and start it up again. It runs like shit and i have to nearly floor it to get it to "snap out of it" , but then it comes back on and off and on and off. But again after running for about 5-10 mins it stops doing it. Could something still be wet underneath there causing this, or did I mess something up? I have disconnected the battery for an hour and reconnected to reset the computer and even reprogrammed the car to stock again with the Hypertech and it is STILL doing it. Please help!!!!!

its probably still wet underneath...when you was using the hose you run that risk...open up the hood and stick some fans on boxes. hopefully that will work

Could it still be wet after driving on and off all day? I probably drove 80 miles today.

Its hard to tell since you make no mention as if there are any error codes, if so what are they.
Depending on where the water went in most cases it runs under the manifold and the knock sensors are recessed and fill up with water and short out.

Well my SES light is already on because of the headers I installed (no simms). However the SES light started flashing a couple of the times when this happened.

Well its been 28 hours and 100 miles later since i washed under the hood. Car is still doing it. If its wet under the hood somewhere still, then why does it run just fine for first 5 mins or so, and THEN run bad, and THEN run fine again until shutdown after that. Seems like the computer is adjusting to something. I noticed it disables the torque converter lockup for about 5 mins after it clears up also.

Any smoke on startup?

Any smoke on startup?


No none I've noticed. Problem seems to be related to the temperature of the car. If its at max temp its fine, and if its cold its fine. Its the in -between when it runs bad. Wouldn't that have something to do with the computer and the whole warm up process? I dont think anything is wet anymore by now. Its been 3 days.

EDIT: PROBLEM IS NOT FIXED EDIT:

PROBLEM IS FIXED !

It turned out to be faulty o2 sensors!!

Both went bad. The misfiring from the car getting wet probably sent some fuel through the exhaust and that probably killed them - if they werent dead already. I knew they were rough when i saw them when I changed the headers, but it never occurred to me that they would be the problem. I was localizing to where the water went.... Anyways my friend has some really expensive GM code reader thingie and it can read and monitor EVERYTHING. It told us the o2 sensors were not working. I swapped them both out and $140 later the car is running great and much smoother overall. I had forgotten how smooth the engine ran I guess I had gotten used to the roughness. Anyways thanks for the help and suggestions everyone!

Ok I have to resurrect this post. Car is starting to run bad again. It's been a week since I installed the new o2 sensors. It's not doing it nearly as often but it has done it like 3 times to me in the last few days - each time lasting only about 5 seconds and it was gone. I'm very concerned that perhaps there is ANOTHER problem that caused my old o2 sensors to die and perhaps they weren't dead after all but something ruined them and now that problem is going to ruin my new o2 sensors!? My biggest thought is that the car is running too rich from the headers and perhaps that is doing it? The egr has been removed also and I still haven't been able to find a proper blockoff plate on the intake manifold - could that be contributing? I thought that would only make the idle goofy. Right now I just have the old egr hose still in there, but cut and crimped (yeah it looks ghetto). Could that be contributing? I really need some answers. I'm scared to drive my car now for fear that I'm gonna ruin my new o2 sensors and have to caugh up another $140 !!! Please help!!!

You could have a header leak which causes the 02 sensors to tell the computer to dump fuel to compensate...which ultimately causes them to fail. What's your gas mileage looking like?

You could have a header leak which causes the 02 sensors to tell the computer to dump fuel to compensate...which ultimately causes them to fail. What's your gas mileage looking like?


Hmm thats in interesting thought. Gas milage has been terrible. But I figured that was because of the misfiring. Its down to about 15 mpg now. I believe I do have an exhaust leak. I have a light ticking sound under the hood which most have said could be exhaust leak. Didnt seem to be anything major though. How big a leak would it take to do that? Would tuning take care of that?

not a very big one. If ANY cold air is entering the headers then it'll screw up your O2 on that side. Depending on the amount of air that's leaking in, depends on how long your sensor will last. It'll start acting funny either way. I had a major leak near cylinder 7 but you couldn't see it. Only way I found it was when we were pulling the motor to replace a piston. Blew the gasket to hell. I hope you have the stock metal gaskets on your headers...if not, I bet that's your problem.

not a very big one. If ANY cold air is entering the headers then it'll screw up your O2 on that side. Depending on the amount of air that's leaking in, depends on how long your sensor will last. It'll start acting funny either way. I had a major leak near cylinder 7 but you couldn't see it. Only way I found it was when we were pulling the motor to replace a piston. Blew the gasket to hell. I hope you have the stock metal gaskets on your headers...if not, I bet that's your problem.

I can't imagine much outside air entering the header considering all the gasses trying to get out. I did NOT reuse the metal gasket. It didn't look very good so I used the gaskets that came with the headers. The car has ran fine for about 2 weeks before I noticed the ticking sound. The misfiring didn't start until I washed the car and hosed under the hood a bit. Later we found the O2 sensors were bad and swaped them and car was seemingly fine, but now everytime I shut it off for a few mins and restart it it misfires for about 5 seconds or so until i get it part throttle and then it stops.