Bad Fuel Pump?

[Pokealong1227]

So I think I found the source of several of my problems but I want opinions. My car struggles when I try to start it first of all. It will rev up for a split second, then drop down to almost 0 RPMs and sound like it's going to stall, then sometimes slowly go back up. It will then run fine for the most part except long drives when the engine gets hot or I hit the throttle hard multiple times in a row. It will then hesitate and kind of stutter on the throttle which jerks the whole car. If this hesitation happens a couple times I start to hear a weird higher pitched noise until I turn the car off for a decent amount of time. Once the noise is gone, the problems usually gone for a while. The sending unit is also bad. When the ignition is in the On position but not started I can hear a 2-3 second mechanical whirring sound, not sure if that is the pump or not.

I have replaced the intake, cleaned the maf sensor, gotten new spark plug wires, the spark plugs are good, let the computer re-learn, and these are the only problems that haven't gone away. They all seem to add up to the fuel pump. I don't have a fuel pressure gauge and don't want to spend the money on one when that money could go toward a new pump. Opinions?

[L36 Killer]

maybe try to rent a pressure guage from a local parts store. Problem could also be a bad fuel pressure regulator. What year car? GT or GTP? How many miles?

[Pokealong1227]

2003 GT 186k. What kind of store would rent those? We have an Oreilys in town and Autozone and Advanced Auto Parts about 15 minutes away.

[L36 Killer]

Call all three, one of them should be able to help ya. If not, just buy one and return it after you're done using it
. I recently replaced my FPR because I was having problems with fuel flow. My car kept running lean no matter how the fuel trims were adjusted. I thought it was my fuel pump going bad. But I decided to replace fuel pressure regulator as a last ditch effort before biting the bullet on a fuel pump. New fuel pressure regulator solved muy problem. Funny thing is, my old regulator showed ZERO signs of failure.

[Pokealong1227]

The only reason I thought the fuel pump might be going bad is because the fuel sending unit is already bad(has been for a couple months). How would I tell if the regulat is going bad? Don't wanna waste money on it if it's fine.

[Pokealong1227]

Oreily will rent a fuel pressure gauge for a refundable $110(refunded as soon as I return it). May see if my mother's boyfriend will go with me later to check it.

[Scottydoggs]

that must be a damn good gauge, cause most of the time the deposit is the value of the tool being rented.

[Max Cook]

I used one from autozone recently. We did it in the parking lot and I only had to give him my cell phone temporarilly as collateral. Also what about the crank sensor?

[dsmuts]

I bought a fuel pressure tester at az for like $20.

[Pokealong1227]

Yep not sure why they want to rent it for so much. I was shocked he didn't say $20 since you can get them for that. Autozone says they won't rent them and won't help whatsoever. You can buy them and that's it. I actually have a friend across town who has one. Gonna use it tomorrow after work. Any opinions on the crank sensor? Some of the symptoms seem kind of fitting, but other than that it would be completely random.

[Pokealong1227]

If this helps at all, it seems that when in Drive sitting still my car idles rough and every now and then kind of jerks. Doesn't stall. Seems to idle perfectly fine when in park.

[Pokealong1227]

Here is a video of the whisting sound it makes after a long trip. About 30 miles of driving today and it is acting up, this is in park with slight revs. The whistling sound is best heard on a phone or device with low bass because the exhaust kind of overpowers it otherwise. Can be heard VERY clearly from inside and outside the car. I can't seem to pin point the sound but my first thought was intake. Does not seem to be coming from intake or throttle body and is a totally different sound from the quiet whine of the intake. Much louder and higher pitched. Standing outside the car it is very hard to find where it is coming from.
http://www.youtube.com/watch?v=PhIkg...ature=youtu.be

[dbextreme]

The reason the rental is so expensive is because it has fittings to fit multiple cars. You don't need all the fittings for ours, just the Schrader valve. I've always wondered if a tire pressure gauge would work, LOL....

Could be a simple vacuum leak...

[Pokealong1227]

Would a vacuum leak really cause so many issues and ONLY after driving for a while(not counting difficult starts) then not have problems after a few hours of sitting? Just kind of frustrating having to troubleshoot so many different issues. We own a 2004 Grand Prix GT also and it's never had any of the issues this one is having.

[L36 Killer]

Have you tried running the car with the MAF unplugged?

[Pokealong1227]

Have you tried running the car with the MAF unplugged?

No I have not. Didn't even know it could start without it honestly. However I am going to go buy autozone if I work tomorrow(on call) and get my codes checked again. Got a faulty MAF sensor reading code last time and cleaned it, if I get it again I'll replace it. My car ran fine all weekend after cleaning it. Could a bad MAF sensor cause this?

[L36 Killer]

yes it could. It could also be the wiring going to the MAF plug itself. If it looks worn and baked (i.e. alot of heat wear) you could buy a new connector and replace it. But definitely check the codes again first

[Pokealong1227]

I will get codes checked asap. Wiring looks fine at the connector but will trace it a bit further and double check.

[Pokealong1227]

Wires look okay, vacuum lines visually seem fine, but I AM still getting maf sensor low volume code I believe is what it was. Same code I had before that went away for 3 or 4 days after cleaning it.

[Pokealong1227]

Cleaned MAF sensor and disconnected battery while it dried and it's running with 0 issues again which will probably last for a few days. Thinking it was probably the battery disconnected that did the trick but not sure.