1991 Pontiac Firebird lacks power(major amounts) and someti

WHITESTONE

MEMBER
1991 PONTIAC FIREBIRD
6 CYL
2WD
AUTOMATIC
252,000 MILES

It used to periodically run poorly - severely reytarded timing (disconnecting the initial timing setting wire would help)

No it seems to run poorly all the time regardless.

Monday, February 2nd, 2009 AT 8:15 PM

6 Replies

LTKNT

MECHANIC
30 POSTS

Based on the vehicles mileage, I would suggest an engine rebuild, or swap. The transmission may need service too. Good Luck!

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Wednesday, February 4th, 2009 AT 11:32 AM

WHITESTONE

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6 POSTS

Thanks for the response!

The engine has been rebuilt so I don't think that the mileage on the car has much to do with this problem since the engine did not smoke or leak at all, and ran great with plenty of power until recent problem. Transmission always shifted great too (about 5200 shift point) but now the motor is sluggish.
Won't hardly go over 3000 rpm at best when driving
(Idle could do better than that though).

UPDATE: The plugs were fouled so I have replaced them now. Maybe too much fuel? I have ordered a fuel pressure check guage and hope to find out soon :-) (21.95 on ebay free shipping )

Maybe bad fuel pressure regulator?

I can't get any "CHECK ENGINE" light readings,
Maybe the bulb is burned out.
Plan to get a diagnostic tool to read the codes
( 5-$10 on ebay probably) Yay ebay!

LOL!

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Wednesday, February 4th, 2009 AT 11:51 AM

LTKNT

MECHANIC
30 POSTS

The check engine codes should be stored in the computer. If the bulb is out, the codes would still be stored. As far as the lack of power gos, there are sevral things that could be causing this: Incorrect ignition timing. Timing chain worn out. Restricted exhaust system. Faulty distributor cap, wires ect. Incorrectly gapped spark plugs. Air filter dirty. Faulty ignition coils. Breaks binding. Transmission clutch slipping. Fuel filter clogged and/or impurities in the fuel system. EGR system not functioning properly. Low or uneven cylinder compression pressures. Air (vacuum) leak at intake manifold or plenum. Good Luck!

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Thursday, February 5th, 2009 AT 9:10 AM

WHITESTONE

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6 POSTS

Thanks for the response and the list of possibilities to check.

Not sure I made it clear that the problem used to come on suddenly and then go away sometimes just as quickly. It would periodically run fine and then not,
whether driving or just sitting in the driveway.
So, can any of these be ruled out?

Though I have replaced the fouled plugs with new, also new cap/rotor, coil, pickup coil (and these test good).

Thanks again!

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Thursday, February 5th, 2009 AT 9:23 AM

LTKNT

MECHANIC
30 POSTS

Rule out the spark pug related items. All others on the check list are worth looking into. Problems that happen, then go away are a sign that something in the car is about to go south. Since the problem appears to have gotten worse, whatever was going bad has went there.

Good Luck with your ride.