Acceleration problems

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Jul 27, 2007 | 12:28 PM

JEGuzzardi

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Acceleration problems

1985 F-250 302 with EFI. New motor has about 5,000miles. Having acceleration problems. Acts like it's starving for gas when I accelerate from a stop. Runs fine on the highway. Great truck otherwise (have owned it since it was a 1-yr-old).

My mechanic did all the normal things. New sending unit, fuel pump, fuel filter. Checked exhaust and cat. converter, and all settings. He doesn't think it's EFI since it runs so well at higher speeds. He's stumped. Just got smog checked and it passed with flying colors.

Have had others say it might be timing chain and/or gears. Is this the most likely? Or is there another issue. I get the feeling that this might be simple...just hard to figure. Just finding the problem is probably costing more than the eventual fix. Any help? Thanks.

Jul 28, 2007 | 08:55 AM

Franklin2

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From: Virginia

Did he pull any codes? Check the vacuum line going to the MAP sensor. I am assuming he also knows the procedure for setting the timing(unplugging the spout connector)?

Jul 28, 2007 | 10:29 AM

pfogle

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From: Oak Harbor, OH

What was done to the engine? Is it a new reman from autozone or the like or a fresh rebuild of your old engine? It sounds like you have a timing problem.

Jul 28, 2007 | 02:25 PM

JEGuzzardi

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The new motor was a new "long block" from Ford. I'm no mechanic, but I think that means the timing chain and gears are from the old engine. If the chain is new with the new motor, then I guess I should look elsewhere for the problem. As for vacuum, spout connector, etc. The mechanic did all that.

I've read other discussions about in-tank filters for trucks with dual-tanks, and/or rusty tanks. Maybe this could be the issue? Especially since the truck is 22 yrs old.

Jul 28, 2007 | 09:14 PM

Franklin2

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From: Virginia

Put a fuel pressure guage on it, and you can see if it's a fuel problem or not.

Jul 28, 2007 | 10:07 PM

sasquatch999

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Where could you get a fuel pressure guage? How would you set that up?

Aug 7, 2007 | 10:12 PM

greyghost85

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From: Lebanon

acceleration problems

if she bogs down at first, then takes off.....i had that prob once, after a rebuild. a drag race buddy popped next size larger carb jets(holly) in, and the hesitation wuz gone!