1989 Firebird Formula 305 TPI idle issue
01-21-2015, 04:45 PM
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Car: Firebird Formula
Engine: 305 MFI
Transmission: Auto
1989 Firebird Formula 305 TPI idle issue
1989 Firebird Formula 305 TPI auto trans. After driving for a while when I come to a stop light or sign an sit my cat start to drop rpms from 700 to 500 sometime more than it will kick to 1000 and drop to 200 or less and die or kick back up to 1000. Also throws a lean exhaust code for a couple minutes then goes off and this happens randomly, I have replaced the TPS sensor, pcv valve, iac valve, fuel filter, spark plugs, O2 sensor, all 8 fuel injectors and I have cleaned my upper intake and throttle body and relearned the idle air control. Also checked for vacuum leaks but found none, I was told to check for vacuum leaks again, do head gaskets, or replace my crankshaft position sensor or distributor. Don't know what to do next please help!!
01-21-2015, 05:01 PM
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01-22-2015, 07:45 AM
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Car: Firebird Formula
Engine: 305 MFI
Transmission: Auto
Re: 1989 Firebird Formula 305 TPI idle issue
I have sprayed the hoses with carb cleaner, soap and water, and there is no noticeable hissing sound.
01-22-2015, 08:34 AM
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Car: 1 Owner 1986 TA with a WS6 package
Engine: 5.0 EFI
Transmission: THM700R4
Axle/Gears: 277 Posi Speedo
Re: 1989 Firebird Formula 305 TPI idle issue
Good Idea,i was going to suggest Starter Fluid.
01-24-2015, 10:27 PM
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Car: 1 Owner 1986 TA with a WS6 package
Engine: 5.0 EFI
Transmission: THM700R4
Axle/Gears: 277 Posi Speedo
Re: 1989 Firebird Formula 305 TPI idle issue
Is the "Service Engine" light coming on??if so what is the Code.
01-24-2015, 11:03 PM
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Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: 1989 Firebird Formula 305 TPI idle issue
Maybe check the fuel psi too.
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01-25-2015, 08:37 AM
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Car: 1985 Z28
Engine: TPI 400 SBC
Transmission: 700r4
Re: 1989 Firebird Formula 305 TPI idle issue
my car did that many years ago, turned out it was the mass air flow sensor. once i replaced it the hunting went away.
on a side note, once your car is at idle disconnect the IAC then drive it to see if it still hunts. maybe it would help to see what component is causing the hunting, it is fuel delivery or air.
when you cleaned the throttle body dont forget to remove the IAC and clean the heck out of its cavity.
on a side note, once your car is at idle disconnect the IAC then drive it to see if it still hunts. maybe it would help to see what component is causing the hunting, it is fuel delivery or air.
when you cleaned the throttle body dont forget to remove the IAC and clean the heck out of its cavity.
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