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[damystikal69]

Here is a problem I'm having. I can start my car and drive for a couple of minutes and its fine. Runs very strong. Then after a couple of minutes it starts cutting out, back firing, acting like its not running on all cyclinders. When it's running like that I can push the peddle to the floor and it clears out. But once I let off of it, it starts runnning like crap again. Then it seems like once my engine reaches a certain temp it starts running right. This all happens every time I drive the car. Any ideas what my problem is?

 

[damystikal69]

Here are a few things I've done to try to fix it. Checked timing, installed new fuel filter, bigger fuel pump, cleaned all grounds, cleaned all connecters. Timing is at 14 degrees, and fuel pressure is at 42 pounds. I've moved the timing and fuel pressure around and no change.

 

[xpeteyjtx]

Pull the codes
Make sure you pull them with the engine off
and then with the engine running. When you pull the codes with the engine running, wait until it starts acting up. Good luck

 

[shallowreef]

Could it be a dirty MAF sensor?

 

[tddpop]

Just a guess here, so hopefully someone here much smarter than me will chime in. It sounds like a fuel or spark problem, like it is running really rich and has a carbon build up problem. It sounds like the fuel tables in the computer are wreaking havoc on the motor, either from bad oxygen sensors, or coolant temp sensor. Have you pulled the spark plugs to see what they look like? You say it runs fine on initial start up, then once it warms a little it runs rough, then once it warms more it runs fine. I would look at replacing the oxygen sensors, how many miles do they have? I would also pull the plugs to see what they look like, and replace them, maybe a cap and rotor too. I would also look into replacing the coolant temp sensor. Check for any trouble codes, do a complete tune-up, plugs, cap/rotor just to do it as the same time as the plugs, and definately oxygen sensors, and if you have a K&N or similar air filter I would clean it or replace it if it is not a reusable air filter. It also may be a vacuum leak problem, so I would check for vacuum leaks. Although you say it runs fine once it is completely warmed up, so it may not be that.

Once you have done all this I would get the car tuned on a dyno, so you can see what your A/F ratios look like, and fine tune fuel pressure and plug gap.

This also sounds a lot like the problems other people have had when using a C&L MAF. Their problems usually cleared right up after switching to a Pro-M, so maybe that is your problem too.

 

[damystikal69]

here are the codes I pulled.
Running: 12,33, 44, 94
Off: 81, 82, 84, 85

 

[damystikal69]

The oxygen censors are brand new, I have a BBK airfilter which I cleaned out while installing the new motor. I am not sure whats up with my temperature sensor. All I know is the temperature guage is way off. I have a buddy that has a C&L on his 95 Cobra and his car runs awesome. I was thinking I may need a hotter plug but not really sure.

 

[xpeteyjtx]

code 12=clean IAB or replace it
code 33,44,94=im guessing you have all the smog/egr stuff removed. Either that or something is not working...either the valves, the solenoids, or the air pump.
I am not familiar with 81, 82, 84, 85... but they are egr related.

I would replace the IAB first, or atleast clean it. Did you remove the smog crap? If so, did this problem occur before you removed that stuff? To diagnose the EGR problem, you will have to test to see whether the EGR valves are actually opening. The solenoids should also be in good shape, one of mine was ruptured. Good luck.

 

[damystikal69]

Yes smog junk is removed. It was removed with the old engine and ran fine. First time I ran codes no code 12. Once the engine got warm thats when it threw this code. I was also reving it while testing. Will this cause the code to show up?

 

[sunil6784]

Probably, because when you rev the engine it bypasses the IAC, and the computer doesn't get a signal from it...just thinking out loud.