gtopercy

I have a 88 Pontiac GTA, 350 auto, with 44k original miles on it. I was taking it on a longer then usually drive today. about 30 mile one way trip.
I got there fine, coming home I set the cruise control and about half way home it turned off, I jumped on it to get back up to speed and it fell on it's face. Felt like fuel starving or clogged cat. I noticed that it seemed fine about 1/4"-1/2" of throttle, any more and it acted up again. I ran it another 10 miles and it started getting worst. I was coming off a off ramp and it was just crawling. Then it seemed to get better and ran another mile or so and at a red light acted like it was going to stalled, it wouldnt' rev, it stalled. I started it back up and barely creeped accross an intersection, I put it in neutral and coasted a bit thinking I was done. I cranked it up and it fired up like new. rev like nothing was wrong, I went to another red light and then jumped on it and took it up to 90mph like it was nothing. then a mile or 2 later it started again, wouldn't take more then 1/2" of throttle. got most of the way home till I got to a hill, it wasn't going to make it. I stopped and started the car and it fired up and I floored it and she went right up the hill without a problem. ????
no check engine light, the bulb works. I was getting a check engine light a while ago, I forget the code but it was low fuel pressure on start. I been able to turn the key on and let the pump run and build pressure before I start it and it's not came back on. I'm think that is leaks down a bit when sitting, blows slow when first fired up also.
I justed serviced the auto trans last weekend but I can't believe that is related.
I replace the fuel pump, filter and sock and clean out the tank when I bought it a couple hundred miles ago as it didn't run.

any help woudl be appreciated.
thanks
Percy

Prickly

I had an EGR valve stuck causing something similar a few years ago. Fuel pumps from auto parts stores are pure **** IMO, they recently took the warranties off the pumps from the parts stores near me due to bad quality. Something you might keep in your mind is a pick-up coil/ignition items/ECU. Run a code check with it running. GL

gtopercy

I was thinking pickup coil also, since it came and went so soon and messed up when rev the engine. I thought a code would of been sent for it but I guess not.

I don't have a way to check engine codes while running.

thanks for you info !!

gtopercy

check engine light came on so I checked it, code 34.
I replaced the fuel filter, but still having an issue. I didn't have the total loss of power but I'm not sure how to duplicate this yet either. I did have the half/full throttle loss of power. Not every time but about 50% of the time. I installed a fuel pressure gauge. has about 35 psi at idle and goes up a bit when reving. when half or full throttle it drops to about 15psi. so that's the problem. I disconnected the fuel pressure regualor vacuum line and it jumps up to about 40psi. so I guess that's working.

I must have a bad "new" fuel pump or something is clogging the sock. I did have junk in the tank but I clean it out pretty well.

I dread dropping the tank, I did 3 of these in a 2 month period.

astrosurfer

Do you have a fuel pump relay?
Have it tested or better replaced if it's really old.
contacts inside relays do in fact diminish over time and it may be experiencing fatigue.
I had exactly the same problem on another car I had.
Everyone said I had a ghost in the car.
It would start and run fine but most days it would run bout 10 miles and then feel like I was running out of gas. But never in the morning on the way to work.
With the new fuel pump I could eliminate that. And the new filter was eliminated.
I could cruise in neutral, shut off the car, cruise for a few seconds dead, re-start the car and all would be fine for another while.
It was weird.

gtopercy

yes, acutally I replaced the relay when I replace the fuel pump. I bought a NEW GM one.
I was under the impression that did work but for initial start up. after the car starts the fuel pump relay should be used. I'm pretty sure you can umplug it and the car will continue to run. If the car holds fuel pressure it will start without it to but it may crank more.
the oil pressure switch does affect the fule pump also.

this fixed your problem?

astrosurfer

actually ...no..LOL
But it was suggested to me as a high possibility at the time.
I merely swapped for a similar relay in the car which worked fine...but it did not fix it.
I actually never did get time to go deep enough into it.
I did tell the chap who purchased the car all about it.
I never did hear back from him so I guess it quit doing it or he figured it out.
I just lived with it.
My 17 mile commute to work could turn adventurous at any time...why would anyone delete that...LMAO.
But seriously...I was hoping it would help you..but I was wrong.
It was a little toyota corolla 4 banger.
Now my commute turns adventurous when someone cuts me off in my "00 bird.
It's great to have the ability to scare the crap out of passengers.
Wish you well in solving this dilemma man.

gtopercy

oh, ok. well thanks for the info. Since I know it's fuel related and I'm assuming the regualtor is working as when I remove the vacuum line the psi goes up, I guess I will be dropping the tank AGAIN. It did have allot of junk in it and I got as much of it out I could. maybe it's getting sucked in the sock. The fuel pump I put in is loud so I will try swapping it out with one that's quieter. Not sure which is the best but I guess a/c delco might be the way to go.

thanks !

WSX123

iTrader: (1)

I have a simialar problem also have the same car, 88 GTA mine runs great on the highway, but when your in traffic or sitting at a light, it feels like it wants to stall, idle is up and down, but while your moving it runs great.

Think mine could also be the EGR Valve

gtopercy

well, that's not the problem I'm having. My problem is losing fuel pressure mainly at half to full throttle and not all the time. While one time I did have the rough idle and stall I think that my problem is the fuel pump sock is getting clogged. Even after I cleaned the tank and replaced the pump and sock only 2-3 months ago.

you could be looking at several area with the problem your mentioning.

gtopercy

ok, I'm fixed. It was junk still in the tank left over from the first pump install. I thought I haad ot all flushed out but apparently not. I flushed it with water this time. was a pain but installed back in and with a/c delco fule pump. works great and nice and quiet.

thanks all !!!