1995 Pontiac Firebird

Tiny
YOUNGZ101
  • MEMBER
  • 1995 PONTIAC FIREBIRD
  • 6 CYL
  • 2WD
  • MANUAL
  • 150,000 MILES
Engine sputters or skips when accelerating. Almost like it has water in the tank or the timing is off. Definite power loss, jerks back and forth pretty severely during acceleration. Car was running just fine, then it sat for about a month, after that is when the problem started. Ran the fuel almost all the way out, used water remover and fuel system cleaner, didnt work. Problem seems to get better after driving for about 30-45 minutes but starts over again everytime I turn off and turn back on the car. No warning lights on, oil pressure is fine. Dont think it could be the timing since im pretty sure its computer controlled. Dont what it is, need help. Will make donation for time if the information is sound. Thanks a lot.
Monday, March 24th, 2008 AT 4:15 PM

3 Replies

Tiny
SERVICE WRITER
  • MECHANIC
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I would lean toward electrical based on it setting and being more promenent in the first colder stages of the running.

Have you check for codes in the computer?

This should be tested when problem is present. The codes may point to certain cylinders that we can start doing a few simple things like moving a plug or wire to see if the miss moves.

I assume once the engine is warm the problem goes away?

How quick is it before heat is felt at the dash from a cold start?
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Monday, March 24th, 2008 AT 9:05 PM
Tiny
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Well it seems to get a little better after its been driving for awhile. It doesnt go away completely. I havent hooked a computer up to it yet, I dont have one. As for heat at the dash, I assume you mean engine heat and not the heater, probably about 20 minutes or so maybe longer. I dont know if it matters but I built a cold air intake for it awhile back but I reset the ECU like you're supposed to so it can adjust to the new air flow and then I drove it from arizona to georgia just fine. Its a strange problem, I noticed this today when I was driving it, when I first get in and take off it runs fine, then after about 2-3 minutes or a mile or two its starts running like crap again. Then I drive it for 45 minutes or so and it gets a little bit better but it never fully goes away. Why would it start off running fine and then get worse and then get better?
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Tuesday, March 25th, 2008 AT 8:16 AM
Tiny
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Is this the 3.8 or the 3.4 engine?

Are you losing any coolant or having to add any?

Both of these engine have had an intake problem. The intake itself on the 3.8 and the gasket on the 3.4.

I asked about the heat (from the blower motor-my fault) as it sounded like a stuck thermostat. Being in the warmer climates, I wouldn't expect it be that radical.

Codes may really be helpful.

My theory:
why would it start off running fine and then get worse and then get better?

IF the engine is hot when you park it, the coolant the came into the engine may evaporate, so it starts okay, but starts leaking back in and has a problem dissapaited it until it gets hot again. This would be more of the 3.8 problem I would think.

If there has been no coolant loss, it may still be an air leak from the lower intake manifold gasket. Sometimes you can flush it out with carb cleaner around the intake gasket area. There may be temperature changes causing expansion and contraction that may seal it at some points. This is more typical or the 3.4

Autozone may be able to read the codes so we can do some testing, I am also suspicious of a MAF sesnor problem.
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Wednesday, March 26th, 2008 AT 9:13 AM

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