Okay, so I bought a 91 V6 firebird with only 77K miles on it. The day I initially looked at it I drove it around and it drove fine. When I came back to pick it up I drove it about two blocks and it spit and sputtered and since the gas show low I thought it needed gas and put some in it. I had to drive it about ten miles on the freeway to my house - it died several times during the trip for no apparent reason and would restart and run until you stepped on the gas and then it would spit, sputter and die again. I got it home and changed the fuel filter, replaced the plugs, wires, cap and rotor (really rusty distributor - had to break away the rotor to get it off) - problem seemed solved.

Then I drove it about two miles, parked and shut it off. Everything seemed fine. I restarted it to go home and about half way back it started doing the same thing again - only MUCH WORSE. I work at an auto parts store and managed to get it there - I dunno how many times I had to restart it, but MANY. Every time I stepped on the gas it would die - otherwise, it would idle fine and that is how I got it back to the store.

I wound up replacing I MAP sensor TWICE since that was the code it was throwing, along with the throttle position sensor and eventually even the computer (but not the PROM). Nothing seemed to help - it would run fine when started, but the minute you stepped on the gas it would spit, sputter and die. Then, I read a post in here about a guy having a similar problem and he fixed it with new fuel injectors - so, I replaced all of those and it finally started an ran whether you stepped on the gas or not!! Hurray!! - right??

Nope, now it runs like crap because the #4 cylinder is dead. I thought I maybe had a bad injector, so I replaced it - still dead. I have had three mechanic friends of mine look at it - one is a 3rd Gen fanatic and he is the one who suggested a new computer. No one can figure this out!! So, I took it to another mechanic - ASE certified - and he thought it maybe had a bad cam, which would be WEIRD, since it ran fine WHEN IT RAN before, but I am desperate so I figured what the hell. He checked the compression on #4 and got 85 ONE DAY and 185 ONE DAY, but after turning the engine over by hand several times he got a consistent 145-55 from all the cylinders. He looked at the lifters and they looked good so he decided it couldn't be the cam. He thought maybe a piece of crap got stuck in a valve and turning it over broke it loose - possibly fixed. NOPE. Still #4 is DEAD.

So, since the distributor was in such bad shape anyway, we replaced it - HOPING that would fix it. Ah . . . NOPE. Now I am considering replacing the motor with another . . . but, before I do that I was wondering if anyone had any ideas?? Yes, #4 is getting spark, and I'm assuming that since I replaced the injectors twice the possibility of a bad one is pretty remote!! Please help - I really wanted to put the $1600 for a new motor into a new paint job!!

 

Did you pop the valve cover and check the valves?

 

Did you test the fuel pressure?

 

Valves checked - look good and fuel pressure is a bit high, but otherwise good.

 

I have a new v6 in mine with 3000 miles and I am having the same problem still. So I doubt its the engine. I am looking into it now. And the only old parts I think I still have on the car is the entire intake system, fuel pump, and tranny. I will let you know more later.

 

Yeah, please let me know what you find out. This has been EXTREMELY frustrating and strange and I NEED the car to use as a daily ride. One thing I forgot was the EGR valve - I replaced that too!! I was wondering about the fuel rail, but the mechanic I took it to said he'd never seen one go bad and it makes little sense that it would be a pump since the other cylinders work fine. What is SO STRANGE is that whe it did run before it ran like a champ - nice and smooth.