Having problems with your 1992 Pontiac Firebird ?

1992 FIREBIRD w/2.8 F.I. WILL BARELEY IDLE. VERY ROUGH. SPRAY 2+2 IN T/B & WILL RUN FINE AT ANY RPM. CHECKED BOTH INJECTOR FUSES O.K.FUEL PRESSURE 45 LBS. REPLACED PASS KEY DECODER. NO CHANGE.REPLACED FACTORY ECM EARLER TOP REPAIR ENGINE CUT OFF AFTER 12 MILES. THAT WAS 4 MONTHS AGO. ALSO REPLACED FUEL PUMP 2 MONTHS AGO FOR NO START & RAN FINEUP TO NOW. I AM AT MY WITS END. HOPE SOME ONE HAS HAD THIS PROBLEM BEFORE. THANKS

Posted / edited by AnonymousUser on : 15-08-2022

Answers :

I have had this same simpletons it drove me craze it turned out to be that the catalytic converter had broke a pace off in side and found it's way down in to the muffler causing a restriction in the exhaust .i have also see maf. cause stall outs I give them the good old tap test and if it stall's replace it. if you cant keep it running long enough 4 that test UN plug it it Will run with out it .hope this help you fix your car .i have 5 of them but only one with a V6 like the body]the ease way to test the exhaust is to drop it just be four the cat. best to you .if this has been any help[ a that a boy ] would be nice but not need 4 me . im just here to lorn to spell . Have a Grate day and thank you 4 using fix ya.please let us know if we have helped and what did it so we can keep passing it on .
Hi.

If engine ir running ropugh when idling , the cause is often a faulty\015\012idle air control valve, an air sensor, or a vacuum leak.

Check also the fuel tank cap, if this does not let air into the fuel tank, then you may experience problems, particularly when idling. Test the car without cap.

The IAC valve is fixed to the back the throttle\015\012body by two torx screws. Disconnect the round shaped connector before\015\012removing the screws.

Before replacing the valve ensure that there is no vacuum leaks. Big vacuum leak can be spotted because of the hissing sound\015\012coming from the leak. To find small vacuum leak you will need an had\015\012tool gauge placed between vacuum lines(eg.Actron Vacuum Gauge).

In\015\012some case MAF and AIT sensor faults can also cause idling problem by\015\012determining an incorrect amount of air to be used in the mixture. In\015\012this case you often get a lean mixture code on the OBDII scanner.

If the failure is related to temperature, then the most likely cause is the IAT sensor\015\012(intake air temperature sensor). MAP (mass air pressure) sensor, MAF\015\012(mass airflow sensor) and engine gas recirculation system may also\015\012concurr in causing the problem.

This sensors are in fact used to determine the quantity of air to be injected along with fuel in the cylinders.
The sensors are located in the air intake.

The\015\012first step in diagnosis is doing an error code scanning. This is done\015\012connecting an OBDII tool to check if there are error codes stored.

If\015\012problem is the IAT or MAF, you usually get lean or rich mixture codes, along\015\012with misfire ocurring when the engine is shutting down because the\015\012incorrect mixture cause flooding or chocking.

Once you are sure that fuel circulation is fine, the most common cause for rough engine when idle is MAF, MAP, vacuum leaks and IAC valve problems.

Regards.\015\012\015\012\015\012\011\011

Ginko.
Repair Help & Product Troubleshooting for 1992 Pontiac Firebird

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