Don't Know How To Explain It....
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Posting Guru
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From: La Grande, OR
Don't Know How To Explain It....
But I'll sure try. Ok, so what is going on is that for some reason, was following a friend up a relatively steep hill going about 35 when suddenly the truck just died(for lack of a better word), shot down to 100rpm, then power came back and it kept going, all with me pushing the throttle down about 1/2-3/4 down. When it came back, kept driving, and by the top (another 200 yds maybe) it had done it another four-five times. First thought, out of gas. Nope, only took 7 gallons at the gas station, and it does it going uphill, or level ground. Second thought, fuel filter, nope, switched that this morning and it did it tonight. So now im out of thoughts....do you guys have any?
Its a 1987 F-150 with a 1994 351W EFI that I've had in for about a year now, and this is the first time I've had this problem.
Its a 1987 F-150 with a 1994 351W EFI that I've had in for about a year now, and this is the first time I've had this problem.
Post Fiend
Joined: Oct 2003
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From: New Jersey
Continue with the obvious things first. This is a fuel/air problem, you checked the fuel filter, so check the air filter.
If that's not it, you might have to dig into the fuel system a bit (fuel pump? clogged/clogging fuel sock in tank?) to determine why your truck is choking.
If that's not it, you might have to dig into the fuel system a bit (fuel pump? clogged/clogging fuel sock in tank?) to determine why your truck is choking.
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From: La Grande, OR
yep, air filter is good, this happens on both tanks, so could it be the pump....do those just go out sometimes (and is there anyway to test)? i thought that it was fuel too, but just to confirm, this couldnt be the AOD slipping hella bad could it?
it doesnt spit or sputter, just the power goes away, the truck stops, RPMS drop, then a second later, it picks up and just goes again. never been in anything like that before
it doesnt spit or sputter, just the power goes away, the truck stops, RPMS drop, then a second later, it picks up and just goes again. never been in anything like that before
Lead Driver
Joined: Nov 2002
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From: Concord, NC
I had a high pressure pump fail once and it would do similar to what you are describing. It failed intermittently with increasing frequency. I finally had to have it towed home where I replaced the high pressure pump and haven't had any problems with stalling since then.
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Posting Guru
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From: La Grande, OR
ok, so i got the new pump in today, and seemed to open up a whole 'nother can of worms......for some reason, my dumb(fillin the blank) decided that it would be a good idea to check those plastic vacuum lines on the EGR valve and the FP regulator, broke both of them (40 degrees, like I said above...my dumb***). got a new line for the FP regulator, but forgot the one for the EGR.
Now to the problem, started it up and now it runs with a lopey idle like i had a big cam in it or something, could this be caused by the EGR not working? The vacuum line is capped off, so there is no leak there, or at the new FP line, but I am at a loss and need to have this going by Friday as I have to go home (300 miles away) and would like to make sure that this is reliable again.......What have I done???
Now to the problem, started it up and now it runs with a lopey idle like i had a big cam in it or something, could this be caused by the EGR not working? The vacuum line is capped off, so there is no leak there, or at the new FP line, but I am at a loss and need to have this going by Friday as I have to go home (300 miles away) and would like to make sure that this is reliable again.......What have I done???
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Post Fiend
Joined: Mar 2002
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From: Bonita Springs FL
The EGR vacuum line being blocked off like that won't cause any drivability problems by itself. It might reduce your gas mileage, but that's about it.
You didn't say you pulled the codes. I would start there. If you have access to a fuel pressure gauge, this would be a good time to test it as well.
You didn't say you pulled the codes. I would start there. If you have access to a fuel pressure gauge, this would be a good time to test it as well.
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Posting Guru
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From: La Grande, OR
i havent pulled codes, and i dont have access to a FP gauge, but I will try and get the codes in the morning, but keep the suggestions coming.
BTW, everything ran fine (except the cutting out above), until I switched fuel pumps, which in there I had to reboot computer (by unplugging battery), so is that why im having this trouble?
BTW, everything ran fine (except the cutting out above), until I switched fuel pumps, which in there I had to reboot computer (by unplugging battery), so is that why im having this trouble?
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Posting Guru
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From: La Grande, OR
ok, pulled codes, got "EGR valve not functioning" (no vacuum, go figure); and IAC valve out of range, but that was it. Replaced the IAC and TPS, and it still has that lopey idle thing, like the FP regulator isnt giving the right pressure or something, i dont know. replaced the vacuum line with small ID air line, but that didnt seem to help, as pointed out above.
Last edited by nighthawk285; Nov 3, 2006 at 12:49 AM.
Lead Driver
Joined: Nov 2002
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From: Concord, NC
By lopey idle, does it sound like it's got a big nasty cam in it? If so, it might be the EGR valve sticking open slightly. You could try blocking off the EGR port on the intake manifold just to see if it makes any difference.
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From: La Grande, OR
Originally Posted by nighthawk285
Now to the problem, started it up and now it runs with a lopey idle like i had a big cam in it or something, could this be caused by the EGR not working?
Originally Posted by EPNCSU2006
By lopey idle, does it sound like it's got a big nasty cam in it? If so, it might be the EGR valve sticking open slightly. You could try blocking off the EGR port on the intake manifold just to see if it makes any difference.