Hi All I have 1990 PONTIAC FIREBIRD 3.1 V6 with PROBLEMS I have read lots of posts on this problem but I have yet found any one with a successful story but I might be looking in the wrong place. well I have a 1990 firebird formula with a 3.1 l v6 engine with 91k miles on it . the problem is you start car runs idle ok for a few the when you depress gas pedal chokes,pukes,dies.
I have change spark plugs , cap , rotator ,wires , egr , fuel ,filter map sensor ,tps ,iac , ignition switch , ignition module. been stumped very much have it now at a good repair shop even he is stumped what do we do from here I not sure where to go with this thing we also checked fuel filter pressure real good , fuel pump is good ,all the obvious stuff distributor we checked but questionable there. tried many thing even firing order as well this is kicking our butts please if anyone can help shed more light on this problem we would really appreciate it.

Thanks

 

Welcome to the forums. I have a V6 3.1 as well. Two of the things you did not mention and were the source of my problems were the fuel injectors and the Fuel Pressure Regulator. Ohm your fuel injectors and make sure they are all good. Also vacuum check your FPR as it may be bleeding gas and choking your throttle response. Hope that helps. Good luck and keep us updated.

 

Ok so vacuum is good no problem with fpr no what we just don t understand why this is acting so crazy side note we took off plug from altenator as a test started car ran a little better but so as you depress pedal bam of shuts the engine .any and all suggestions welcome thanks in advance

 

by the way when put plug back on altenator chokes engine down worse can we have a bad distributor? ecm ?or fuel injectors ? thanks again

 

If you haven't already ohm your injectors. Mine ohmd between 11 - 13 ohms. My bad ones ohmd at 6 and 8. Below 10 they are probably bad.

 

thanks antares57 we will have to try that. does it sound like a ecm or distributor problem at all to you by the way

1990 3.1 v6 91k original miles 2nd owner bought from older gentleman who took very good care of car he was only selling because he has health issues sorry to say

 

If you have a timing light you could check timing, particularly if you moved the distributor at all.. The ECM would probably be the last thing once you've verified all else is good. When you took the plug from the alternator it lessened the load on the engine so it's going to run better. It should be running with the load you have on it including the alternator.

 

Hey I have a 1990 Firebird myself been through the whole nine yards every sensor relay injectors fuel pump pressure tps cold air intake sensor had same problem for a while EGR valve also it stopped for a bit then it turned out it was bad wire harness and ground for the motor when I would step on the gas the ground wire wood shake and shut the car off even before that replaced CPU 3 times wire harness cost me 20 from junk yard ground wire use new ground wire10 bucks online eBay sandpaper to clean contacts for the ground hope that helps let me know if that helps or not

 

You have to check the injectors. If they are not good nothing else matters. Also, you need to smell for gas in the vac line that goes to the FPR. Even a hint of gas smell means you need to replace the diaphragm. But in a '90 car it probably needs to be replaced anyway so you could do it when the plenum is off to check the injectors. If the injectors are original they probably need to be replaced too. Have you checked/cleaned the idle valve passages?

 

had the same problem and fixed it. i had two bad injectors and they finally kept my engine from starting. replaced the whole set and it started right up.