Anyone have some really intelligent reasons why something like this would happen. I've been reading alot of similar situations and also putting in alot of work to figure out the problem. So my conclusion is correctly gapped spark plugs, changed fuel filter, changed fuel pump, changed to chevron techron premium gas only, ran a few bottles of chevron fuel system cleaner, fixed all possible vaccum leaks, and took out intake manifold and put new gaskets plus cleared out egr system. The only time this is reproduced is when fuel tank is 1/4 tank empty. Some suggestions say fuel filter, fuel pressure regulator, clogged injectors, and even weak fuel pump. I know for sure there is power loss from fuel system something is clogged or there is not adequate fuel pressure. If you floor it it takes time before it does what it should do. Any new suggestions would be nice and reasons maybe why you're leaning that way. Thanks in advance.

 

no idea, gapping the plugs wouldnt do anything . i know what you mean tho, sometimes i gas it but it doesnt feel like its gasing, and when i gas it harder then it pulls very slowly . usually its due to my low speed and the transmission being on 4th . try seafoaming it to get rid of the junk

 

Fuel pumps can become intermittent and stall or hang. When stall happens does the car start immediately afterward or do you have hard/no start? If hard/no-start, try hammering the fuel pump w/ repeated on/off/on/off's of the keyswitch to overcome the stuck pump. Only fix is to replace the pump,..if this is your problem.

good luck

 

I can start immediately after stall but do you really think the pump can be bad so soon I bought an aftermarket fuel pump assembly with everything just sit, bolt and plug type of deal. Spectra Premium from rockauto.com it was better than the airtex one which I heard was crap. So I bought this one and even when I install it it wasn't very high on fuel and hadn't had a problem until recently. I ran it all the way down below 1/4 tank and it stalled once last night still had chevron fuel system cleaner going through it so I waited til today to gas it up. I noticed my rpm's dropping to about 400 when stopped and at below 1/4 tank. I also noticed the gas pedal being "spongy" on and off acceleration and also taking longer to crank when starting when below 1/4 tank. I really can't understand what's wrong because the pump seems to be working great very quiet and no hard cranking in the morning. The being at an incline theory doesn't pertain to my situation if its going to stall it's going to stall. Again any ideas would be much appreciated.

 

Pump could be overheating. The fuel in the tank keeps the pump cool, low fuel could let the pump get warm, causing it to pump slowly, and create less pressure.

I can't think of anything else that would cause those problems only when you have 1/4 tank.

Just an idea

 

Did you install the inlet filter screen w/ the pump? A small piece of trash might cause the pump to hang up, but this seems unlikely. Pump is mounted in a baffle arrangement that insures fuel remains available when you brake (fuel runs to front of tank, but baffle w/ relatively small inlet holes at bottom prevents fuel level from dropping).

How do you know that fuel pressure is low? Have you measured? You can connect a fuel pressure gauge and tape to windshield to allow full time monitoring and know for certain.

good luck

 

Okay so the baffle is the plate inside the fuel tank right where the screen on the end of the fuel pump sits correct? Like I said buying the assembly made it more simple to do the task just sit, bolt and plug. So I sat it down inside just like the original, everything on the assembly was already connected so no work for the fuel pump assembly itself. Then I bolted it on the top of the fuel tank I did add a little grease on the gasket so it wouldn't go anywhere. Then just plug it in and ground plus connect all the fuel hoses back in place from the front end. I'm starting to think I just bought crap, canadian made, I had so much faith it wasn't going to give me any problems. Any more ideas?

 

Alright here's the update popped the hood let the car idle for a while and heard a hissing sound like air let out looked for the source and found it to be either the intake manifold gasket or something with the fuel injector. It's coming from the right side if you face the engine around fuel injector number 1 on the top of the rail. Do you think this is a bad injector o-ring I didn't install new ones when re-installing the manifold. If so where should I purchase them is Kragen/O-Reiley's okay? How common is this? It's not leaking any fuel just hissing. Any ideas? No there wasn't any vacuum hoses around except for the FPR and those two were connected.