95 z71 rough driving
July 22nd, 2009, 5:42 PM
#12
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July 27th, 2009, 12:47 PM
#13
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Well I think it now comes down to the fuel pump. but does a fuel pump slowly go like this? My experience with the pump is that they just die, outright. can they go slowly?
July 28th, 2009, 11:55 PM
#14
I've never heard of that, not to say that it cant happen of course. But i"ll give you the same suggestion that was given me (that i havent had time or money to check yet). It sounds like it could be the pressure regulator diaphragm in the tbi unit. My guess would be that it isnt holding the pressure high enough when you are at wider throttle settings. Although, that could also mean the pump isn't providing the proper fuel volume.....
July 29th, 2009, 12:02 AM
#15
Oh yeah, and i was told that vapor lock is impossible on fuel injected vehicles. And then i was stuck in traffic on an uphill grade in hot weather. The truck start missing sporadically, sputtering, got worse and more frequent till it died and wouldnt restart. At least not till i popped open the hood, and waited ten minutes. Started right up, and drove fine.
July 29th, 2009, 2:33 PM
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I have put a bit of money into it and now at this point I need to get a decent diagnosis before I spend myself blind on parts. I have the pump and new screen and as soon as I get through this tank of gas I am doing the work. Will let you know how it plays out.
July 30th, 2009, 11:21 AM
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FOund out last night that the distributor is loose (dummy me grabbed it and it turned real easily) got a timing light on it and have set and tightened it.
Question, would a loose distributor cause my issue?
Question, would a loose distributor cause my issue?
July 30th, 2009, 4:02 PM
#19
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Fishbrain,
Check your fuel pressure at the fuel rail. There is a nipple on the fuel rail made for this. I don't know what the specs are for that model truck, but it sounds like low pressure to me. It takes less pressure at idle than it does at higher rpm's. It sounds to me like the pressure is very close to its lower threshold and when your pump stumbles, it drops below the threshold.
Pumps do not usually go out all at once. Except in cases of mechanical or electrical failure, they slowly lose presure until they fall below the adequate threshold, you just do not know there is a problem until all at once. I had an F150 once with dual tanks and it would do exactly what you are describing, then it might clear up for a little while, then it would be back. If I swapped to the other tank, it ran fine.
Check your fuel pressure at the fuel rail. There is a nipple on the fuel rail made for this. I don't know what the specs are for that model truck, but it sounds like low pressure to me. It takes less pressure at idle than it does at higher rpm's. It sounds to me like the pressure is very close to its lower threshold and when your pump stumbles, it drops below the threshold.
Pumps do not usually go out all at once. Except in cases of mechanical or electrical failure, they slowly lose presure until they fall below the adequate threshold, you just do not know there is a problem until all at once. I had an F150 once with dual tanks and it would do exactly what you are describing, then it might clear up for a little while, then it would be back. If I swapped to the other tank, it ran fine.
July 30th, 2009, 8:35 PM
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yes, it could be because your distr./timing. when i had me heads cleaned and surfaced and reset the timing, i unpluged the wrong wire needed to set the timing correctly so whenever i would put my foot in it just a little, the Throttle body would spit fuel up and about die. when i set the timing correctly, it was fine.