Problems with my firebird! Please help

[85cutlass]

Ok I'm new to this forum but iv owned the car for a while. It is a 1994 pontiac firebird 5.7 lt1 with a 6 speed behind it. The Car when driven a long period of time runs fine but if you turn car off and wait about 10min or so then restart car it sputters and backfires. The sputtering and backfiring stops after about a minute or two of driving. Iv had problem for about a week or two now. Originally when this all started the car wouldn't run above 4000 Rpms. The fuel filter was clogged so I replaced it. The problem went away and now I have the problem when hot and you restart it runs like crap. I changed the o2 sensors, fuel filter. Fuel pressure is 40 running. If you can give me any input on what might be the problem I would greatly appreciate it. Thank You Russ

[Workman]

Originally Posted by 85cutlass

Ok I'm new to this forum but iv owned the car for a while. It is a 1994 pontiac firebird 5.7 lt1 with a 6 speed behind it. The Car when driven a long period of time runs fine but if you turn car off and wait about 10min or so then restart car it sputters and backfires. The sputtering and backfiring stops after about a minute or two of driving. Iv had problem for about a week or two now. Originally when this all started the car wouldn't run above 4000 Rpms. The fuel filter was clogged so I replaced it. The problem went away and now I have the problem when hot and you restart it runs like crap. I changed the o2 sensors, fuel filter. Fuel pressure is 40 running. If you can give me any input on what might be the problem I would greatly appreciate it. Thank You Russ

Okay so it sounds like your Opti could be possibly going bad, How many miles are on the car? Or you could just have some trash in the fuel lines thats coming out.

[ws6muscle]

Spark plugs or fried plug wires could cause this too.

[Workman]

Originally Posted by ws6muscle

Spark plugs or fried plug wires could cause this too.

That is true, make sure you check them.

[Mystery Bird]

ICM will also cause problems when hot. You could try the spacer mod to see if it helps.

[R3DLT1]

Originally Posted by Mystery Bird

ICM will also cause problems when hot. You could try the spacer mod to see if it helps.

Werd. Its easy n cheap.

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[85cutlass]

Alright I have a set of plugs I'm going to put in this weekend. The car has 126,000. But the motor was replaced and I'm not exactly sure how many miles are on it. I ran car around yesterday for about a half hour with my scanner hooked up to it. The only code I have on the car in an AC pressure sensor fault, which I don't think that would affect the way the car runs. I was looking at all the sensors while driving, they all look good everything looks in spec, no sensors were lagging. Ill try plugs this weekend and let u guys kno. Thanks also the icm and coil are fairly new, I replaced them maybe a year or so ago.

[cocobolo95]

Never assume parts are good because you replaced them a short time ago. New parts can fail quickly. Since you replaced the icm, did you put heat sink compound on it's back and on heat sink? If no, even a good icm can go bad quickly without the compound on there.

[85cutlass]

Ya I used dielectric grease

[95 Firehawk]

Originally Posted by 85cutlass

Ya I used dielectric grease

Not the same thing as thermal compound.

[85cutlass]

Alright ill check that out thanks

[Mystery Bird]

Dielectrical grease does not transfer heat, you need to change that ASAP. Thermal grease only.

[85cutlass]

Alright so I did plugs, and I ended up removing air pump because it was in my way. The car still does the same thing, this time I ran it for a while shut the car off when I got home. Went outside a half hour later and it started sputtering and backfiring. I drove it down the block and it cleared up, now runs fine. Ofcoarse when this happened I didn't have scanner hooked up2 car to see what was going on. Any more ideas

[Workman]

Check that ICM coco knows his stuff lol =] And another thing, Does it run hot??? Like operating wise? At idle how hot does it get, and while driving how hot does it get?

[85cutlass]

With the scanner hooked up it runs at like 208 all the time. Idling, driving the highest it goes is 210 degrees