Stumbling and bogging on acceleration

[FormulaSlickG94]

Hello,

I'm having an issue on my 94 formula. When the car makes a cold start, it takes awhile for the car to start....especially when it is hot outside. Also while I'm accelerating the car is bogging and stopping/starting acceleration. The opti was recently replaced (about 25 k) the plugs/wires/coil was done a few months ago. Does this sound like the fuel pump?

[DJ Taso]

I've got the same problem with my '94. I serviced all the parts you described, and I believe it is my fuel pump. But I've also heard if it's a fuel pump problem, the pump doesn't gradually start to die, either it works or it doesn't.

[xxRillixx]

It does sound like the fuel pump... apparently these things go out alot (stock pumps). But im not sure why its taking longer to start.

[xxRillixx]

I've got the same problem with my '94. I serviced all the parts you described, and I believe it is my fuel pump. But I've also heard if it's a fuel pump problem, the pump doesn't gradually start to die, either it works or it doesn't.

I disagree... My fuel pump is 'going bad', it still works, but is only putting out 30 psi w/ the vacume line on and 41 psi w/ it off. Sitting at a light i can feel the car getting more gas, then less, then more... (also raises & lowers my oil pressure gauge). So i have a pump that is no longer good... but its still driveable. Eventually it will just crap out, and i will have little to no pressure.

[DeWynter]

It may be that the check valve is also not working so that would explain the long start time as it has to push fuel back to the motor from the tank.

[FormulaSlickG94]

[QUOTE=xxRillixx] Sitting at a light i can feel the car getting more gas, then less, then more... (also raises & lowers my oil pressure gauge)QUOTE]

Yeah...I forgot to mention that part...sometimes it will rev and give itself gas up and down at stoplights

[Detroit_Bird]

I just went through the same thing- took a week of running like progressive crap to actually die- usually i could feather it and make it run fine, but anything resembling heavy throttle resulted in stumbling. Turned out to be the fuel pump.

Keep in mind a stuck regulator can give the same symptoms as a dying pump.

[DeWynter]

You should see some movement of the oil pressure guage whenever there is rpm movment. It may also have to do with the fuel pressure regulator, as that fuluctuating can cause jumps in rpm.

[xxRillixx]

You should see some movement of the oil pressure guage whenever there is rpm movment. It may also have to do with the fuel pressure regulator, as that fuluctuating can cause jumps in rpm.

Im pretty sure its not because of the regulator... i think that just keeps the pressure from getting to high (over 46-47 psi). I wouldnt think it could cause the pressure to be lower then that. (unless you had an adjustable one that was adjusted too low)

[94T/A ADZE670]

I had a bad O2 sensor give me a similar symtoms.

[FormulaSlickG94]

I kind of forgot to mention that the car has 108 k miles on it and still has the original fuel pump...I guess it might be time. I haven't looked into the O2 sensor though...wouldn't that throw a code?

[Joe 1320]

When diagnosing fuel suspected problems, use a fuel pressure gauge with a hose long enough to tape to the wipers. Observe your reading both at idle and at WOT. You would be suprised how many times it checks fine at idle and dies out under load and rpm.

[93blackta]

my car had a hard time starting. i thought it was an ignition problem but it turned out to be leaking injectors. i replaced the injectors and it starts right up now. btw my stock pump lasted to 180,000 miles

[xxRillixx]

Im at 58,500 miles, and my pump is going out. 93Z