Bucking like it's running out of fuel, then it'll take off!!! ???!??! @$%#$%#$%!!!!

[Larry Hampton]

This has been happening when it's pulling, back off the throttle a bit and it smoothes out. Then this morning on the way to work, it acts up like it never has before. It starts and idles fine. Started happening when pulling hard, like wrapping the gears out, and it's slowly regressed into where it's doing it almost all the time.

I don't currently have a back seat in the car and I can hear the fuel pump okay. A while back I was fighting a problem and switched out the VAF which wasn't the problem, having my wife bring the old one back to me later today. I also swapped fuel pumps with another car while fighting the problem and that wasn't it either.

I'm thinking:

1. VAF
2. TPS
3. IAC
4. FPR
5. Fuel Pump
6. low battery

I add low battery because Sunday I noticed a burnt smell and dim headlights. Opened the hood to see the alt belt flipped over running upside down in the groove, barely made it home. Swapped out the belt last night and it runs like a champ, not batt light. It's a pretty new battery, like 6 months.

[Zcallicutt7]

sounds like VAF to me

[Flw Sock]

If this is what I think it is, I may have had this problem in a few of my cars, and it was a simple fix.

All I had to do was change out the plugs and wires, and check the distributor for water.

[koRnhead]

Its the vaf, or a tear in your intake tube. Not plugs and wires.

[Team Lightning]

It shouldn't idle if it's a vaf issue. Mine wouldn't idle when I unplugged it to check it. Also, I had a leak in the pipe and it wouldn't run or idle.

[Zcallicutt7]

When I had small crack in the intake hose (after the VAF) it was getting unmeasured air which made my car lean, idea was rough/smooth mix (since it was a small crack) and it ran like crap. Ran black electrical tape around the hose neatly and it fixed the issue. Of corse I purchased a brand new VAF (after braking mine) and it didn't fix it 100% until I checked the hose and found a crack....

[bravekozak]

http://forum.e46fanatics.com/showthread.php?t=856781

Check terminals in connector?

[Larry Hampton]

I should have added fuel to the list maybe. I went to the bank an hour ago, it had been sitting 2 hours in the cold, it's below freezing here, and it ran a lot better, like it did when I first left the house (work is 22 miles from home). Bank is a couple miles away, leaving bank it started doing it again, but not as bad, so I stopped for some 100% 87 octane (which is all I run in the car) just a couple gallons, and it's better, not gone, but better. I was wondering if maybe it's bad winter fuel? I always get gas from this one company, at one of 3 different stations, none of which is more than 6 years old and are at locations no gas station ever existed before.

I have the VAF in hand, getting ready to go outside and swap it out. I do need to check the plugs, since I've put this VAF on, the car seems to get worse fuel mileage by about 4-5 MPG and I've had the thing on 6+ months.

[Team Lightning]

Is it possible that you might have some water in the fuel? With all the temp changes around here, I'm thinking maybe some condensation might have collected in the tank. Not sure about your area, but we had a temp swing of around 40* here in Georgia yesterday. High around 65 and lows in the 30's.

[zoom zoom]

I have a very VERY similar issue with an 87 f150 right now and my neighbor scrapped an old/junk 94 protege over the same symptoms when he couldn't figure it out. I've been told by guys on the ford truck forums it's the pip sensor but haven't had a chance to replace it yet. I swapped the tps on the neighbors protege and it didn't help. My best guess is it's the distributor. The ignition pick up. Have you tried a different disty? Heck for all I know it could just be the stupid little coil going bad. I seriously doubt it's fuel related. Pinch the return line with some vise grips to test the fpr.

[zoom zoom]

The truck I'm referring to is to a point the protege was, you can barely touch the gas get it around 1.5k, start letting off the clutch and it revs to 4k+(which is a LOT for a Inline 6) then calms down/bogs down and sometimes stalls. Then you can't get it started again until the thing decides it is ready.

[David88]

If this is what I think it is, I may have had this problem in a few of my cars, and it was a simple fix.

All I had to do was change out the plugs and wires, and check the distributor for water.

I had the same experience FWIW.

[Icedawg]

I had this problem with three different reasons
Festiva - plugged fuel filter one time and working but dying fuel pump another time
RX7 - water in the gas
RX7 - something wrong in the carburetor in a car that had been sitting for years, faltering just when the second pair of barrels opens, i.e. dumps in too much fuel for the air intake - not all that likely to be relevant to the FI Festi of course.

[Larry Hampton]

Okay, I swapped the VAF, didn't help much. The closer I got to home, the worse it got, but never as bad as this morning. I pulled the plugs, they looked good, gapped at .038 as when I put them in, also ran comp test, 136, 142, 145, 149. So I pulled the pump, tank looks good. Probably swap coil tomorrow.

[FestYboy]

look for arcing at the coil tower or the iron core that surrounds it. you can also do a water spritz test before swapping parts.