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Slow Acceleration

I have a 92 F-150 351 V8 with auto trans (E40D). I am experiencing slow acceleration in the first couple of gears. If I press the gas pedal

slowly acceleration is fine but when the gas pedal is pressed past a certain point the truck seems to get bogged down. If I then let up on the

gas pedal it seems to recover and start to accelerate again. I can hear the fuel pump turn on when I turn the key to the on position, all fuses

seem to be OK. This is most noticable in the last half of the first gear and through the second gear when the RPMs are high. At higher speeds

(45 and up) it isn't so noticable until I get to a steep grade, but it doesn't usually get as bad on a grade as it does in second gear.

Anyone have an idea what to check or what the problem is?

Thanks.

Reply to
Joe
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Forgot to add...

In the morning (or after the truck has been sitting for a while) it misses when I try to start it. Sounds like there are 1 or 2 cylinders that aren't catching. This is easily corrected by tapping on the gas pedal for a second. If the truck dies before I can do that then a second restart USUALLY starts without missing but sometimes it does start to miss the second time, again, tapping on the gas pedal for a second fixes it.

All of this started happening in the last week or so. The poor acceleration is getting to the point where I can notice it. The missing while starting has been happening for a few days or so.

Reply to
Joe

Plugged fuel filter???

acceleration

Reply to
el lobo

Ya, I had that thought too (fuel filter). Replaced it last night...took truck to mechanic this morning. I think the fuel filter fixed the problem when starting but the other problem seems to be worse one day later.

hmmm...

Reply to
Joe

O2 sensor? Those go bad.

I wonder what are the symptoms of a bad MAF Mass air flow sensor?

Reply to
Eastward Bound

Well I called mechanic, they said the cat converter is bad (got that info from truck computer). They sending to muffler shop to confirm. I have had the truck for 85K and have never replaced them. I am not convinced though, seems too easy.

Joe

experiencing

Reply to
Joe

I'm convinced. An obstruction in the exhaust can cause running problems.

Think of it this way. If you had to run 10 miles and you can only breath through ONE single nostrile how well would you run?

Your trucks engine needs to breath the same way us humans need to breath.

An air flow obstruction in intake and/or exhaust can cause running problems.

Reply to
Eastward Bound

It won't matter. The '92 was speed density system w/no MAF.

Reply to
lugnut

Watch your tech. There is no converter check or code in '92 F150 ECM. Converter can only be checked for obstruction by drilling pilot hole forward of converter and checking back pressure or with an intake manifold vacuum guage. Failed converter will cause observed symptoms. If that is the problem, you will need to followup by finding out why the converter failed and repair the primary failure. Converter failure is, many times, collateral damage.

Reply to
lugnut

Reply to
el lobo

Reply to
el lobo

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