Fuel pump problems?

I have a '92 grand prix se 3.1L V6:

Ok so i had a guy change my fuel pressure regulator. It worked for like 5 minutes when i drove off and now its still doing the same kinda thing. It feels like its missing. I give it like pedal to the medal and it hesitates goes hesitates goes and then once at like 30 mph it finally starts going. Also, it idles badly in the beginning and then it goes up to about 1000 rpm and then the check engine light comes on. Yeah so he kept saying something about a vacuum leak and he checked and did find a hose that wasnt on all the way and that fixed the problem, until i woke up and it was crap AGAIN!

Could air have gotten into the system that needs to be bled out or does it sound like a bad fuel pump. I had it diagnosed by computer for 90$ that it was the fuel pressure regulator. Also i changed all my spark plugs so theyre not the problem. ANy ideas please help its driving me crazy.

I would check fuel pressure at the schrader valve. That will either put the finger on or eliminate the fuel pump as the culprit. How old are the plug wires? Check engine light on?

Cycling the ignition on/off multiple times will run the fuel pump and purge the air out of the system (if there is any).

Your best bet is to get a fuel pressure tester and check the fuel pressure right when you turn the ignition on. The pressure will spike and then drop down a bit. Then turn the car on and check that pressure.

Then with the engine idling, pull the vacuum line off at the FPR and check the pressure. The differential between the pressures with the FPR activated/not activated should be no more than about 7psi.

You're not going to get this kind of info from a system scan.

Cycling the ignition on/off multiple times will run the fuel pump and purge the air out of the system (if there is any).

Your best bet is to get a fuel pressure tester and check the fuel pressure right when you turn the ignition on. The pressure will spike and then drop down a bit. Then turn the car on and check that pressure.

Then with the engine idling, pull the vacuum line off at the FPR and check the pressure. The differential between the pressures with the FPR activated/not activated should be no more than about 7psi.

You're not going to get this kind of info from a system scan.
Before he installed the fuel pressure regulator he mentioned something like i had 0 pressure or something like that which he thought was odd.

I would check fuel pressure at the schrader valve. That will either put the finger on or eliminate the fuel pump as the culprit. How old are the plug wires? Check engine light on?
I dont know how old the wires are probably stock i would guess. Thats a good idea because maybe my #6 wire is faulty. *Service engine soon light, yeah that one.

I just went out and cycled my ignition it kinda seemedlike it works but the SES light is still on and it idles very weird. When i start it goes real shaky for about 2 seconds then it goes up to 2000 rpms (thats usally when the SES comes on too) then it gradually goes down towards 1000 rpms.

Yeah so i guess i didnt change my spark plug wires would that cause that hesitating?

If you have an Advance Auto or Auto Zone in your area, they will can you car for free to determine what tripped the check engine light to come on. Normally, if it's a mis-fire, it will trip a p030x (the "x" being the cylinder number causing the mis-fire ex-p0301 would be mis-fire on cyl #1) or p0300 which indicates multiple mis-fires. If mis-fires are indicated, and you haven't changed the wires, do so and see if it clears up. At any rate, have the car scanned and post the scan results, it will help us determine you next path of action.

If you have an Advance Auto or Auto Zone in your area, they will can you car for free to determine what tripped the check engine light to come on. Normally, if it's a mis-fire, it will trip a p030x (the "x" being the cylinder number causing the mis-fire ex-p0301 would be mis-fire on cyl #1) or p0300 which indicates multiple mis-fires. If mis-fires are indicated, and you haven't changed the wires, do so and see if it clears up. At any rate, have the car scanned and post the scan results, it will help us determine you next path of action.


If you check his original post, this is an odb-i Grand Prix. Just for your info.

Whoops, thanks Bob, I was dealing with another similar issue and got the two confused.

Im gonna get some new wires tomorrow. Man this car has gone downhill fast jesus.

Could i possibly have a bad CAT converter?

Im gonna get some new wires tomorrow. Man this car has gone downhill fast jesus.

We had a '91 GP 3.1L and it was a maintenance pit. Harmonic dampener, injectors, intake gaskets, alternator, a few sensors, etc. in right about 100K.

On the contorary, my 97 GP 3.1L has had the intake gaskets go out. Everything else was normal maintenance.

Ok so now i just put all new wires on and it still idles weird. BTW the wires were original at 160,000 mi a few looked pretty bad. It really seems like nothing changed by putting the new wires on. What could be the possibility now?

When you changed the wires, did you inspect the plugs? It's possible that the new plugs got fouled out by the bad wires.

No, for some reason i just dont think the spark plugs are the culprit. Im pretty sure there is a vacuum leak SOMEWHERE but i cant find out where. Everything that is visible like the intake module thing on the back of my engine everything is fine and i used a spray bottle and checked for leaks and nothing. It seems like when i have my heat on it wont die. I was idling at a stoplight with a downard slope and it felt very weird. The rpm and oil pressure both went down like to almost 0 pretty fiercly then went back up to about 1000 rpms and the back down until i went. Also, sometimes when im backing out of my driveway when i stick it into drive and am about to go it just shuts off but it always starts back up. Any new problems you think because i seriuosly dont think it is the spark plugs.

any new problems it could be?

Ok, so now it idles bad at first but then runs decently. Usually my car runs fine up until it gets warm and then it starts hesitating more and wants to almost die at stoplights, usually if my car is on a down hill slope. I cannot figure this out.

With it acting up on a slope, it puts it right back to a fuel pump issue. Until you check fuel pressure and post the results, we can't help you because you're guessing the fuel pressure is ok when all your symptoms point to it.

Would a computer read a failed fuel pump?

no, it wouldn't

Ok guys after all this hastle i took it to a new guy and the problem was that the last guy broke 3 vacuum lines somewhere behind the intake. SO yeah $60 and it runs perfect.

excellent, the broken vacuum lines affected your fuel pressure because those lines feed vacuum to the fuel pressure regulator off the throttle body vacuum port.