missing when cold

**95Firebirdred** · 04-28-2009, 07:26 PM

when my car is cold and i get into it it will start missing around 3500rpms. But when the car gets warm it dont do it. the car has all new ignition on it. Any ideas on what will cause this.

**JaycenK** · 05-02-2009, 09:15 PM

make sure you wires arn't burning on exhaust and make sure your plugs are tight and not backing out.
Is your Check engine light on?
Did you change plugs and wires?
What was replaced as far as the ignition?

**95Firebirdred** · 05-02-2009, 09:20 PM

Everything has been replaced and the wires are not touching anything. I noticed that it only does it at full throttle.

**side2000** · 05-03-2009, 07:39 AM

why are you rippin on it cold?

**JoshieDoom** · 05-03-2009, 09:52 AM

Originally Posted by side2000

why are you rippin on it cold?

Exactly.

**tnthub** · 05-03-2009, 12:49 PM

Sound like moisture... In the old days a cracked disty cap could do that... maybe there was a little moisture around the opti? You said "everything" was replaced... It is generally more common today for electrical problems to occur after things heat up...

You should not have the engine at full throttle until it is fully warmed up or you will damage it. Perhaps the system is sensing too much valvetrain clatter or header noise when things are cool and the knock sensor is retarding the timing?

**JaycenK** · 05-03-2009, 05:53 PM

I'm with TNTHUB. If I don't get mine warmed up all the way it lets me know on the top end. I have long tubes and ORY so my knock will go nuts anyway and if I'm not quite up to temp it pulls so much timming that I get a little miss up at 4000.
Do you have any mods done to the car?
OPTI was replaced with a new GM unit?
Do you have a tune or power program running on the car?

**95Firebirdred** · 05-04-2009, 08:16 AM

i get into it when the car runs about 15 mins. The temp needle is about halfway to normal running temp.

I have little mods done. Bored .30 over 3 19 cam Bigger valve springs I think it is ported and polished but i am not sure. My dad had all the machine work done on it but i am not sure what all they did. I have a new and tuned computer done by a performance shop where i live.

I dont know if this makes a difference but i have rapid fire plugs and 8mm wires and i have a small exuast leak at the header flange. The check engine light does come on ever now and then but i havent had it read cause i figure it is from the exuast leak. Its running a little rich.

**JaycenK** · 05-04-2009, 08:47 AM

Exhaust leaks shouldn't cause a rich condition. It sounds like the programming may be off a bit if nothing else is wrong. If you don't think that is the case then you have to start testing parts like the mass air, TPS, & MAPS to make sure they are sending the right values to the pcm. If you have a chiltons it is all in there how to test it. All you need is a multimeter. An easy way to check al of that is to go back to the programer and have him hook it back up and find out what values the pcm is seeing through his software and make sure it isn't something he needs to fix. Depending on what program he uses to retune with he can see alot more than you will be able to with a multimeter and he will be able to see if it is throwing codes. Just a thought but I would pay him a visit and see. If he has already done the work and now you are having troubles, he should not have a problem hooking it up and double checking his work.