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Discussion Starter #1
As the title says....I am about ready to drive this truck off a cliff if I can even make it to a cliff.I have changed plugs,wires,cap ,rotor, ignition control module,coil,crank angle sensor fuel filter,air filter and tps. I have cleaned the maf changed most of vaccum lines dropped the gas tank{drained,washed and dried},bl ew out the fuel lines,ran a fuel pressure test[ was correct per the manual]. I cannot for the life of me figure out what is wrong with this truck.

It is an 87 hb se v6 3.0. I fire it up and runs fine for a minute or two then decides it wants to stalBartl.I start it again and same thing happens. I take it for a drive and it runs good for a short time then all of a sudden it feels like I have taken my foot off of the accelerator.If I hold it steady it returns to normal but only for short periods of time. I took it camping in september and it ran like a dream. Now it is garbage.
There are no codes given in the computer.
Anyone think they can help.It would be greatly appreciated.If no then I have no choice but to junk it.

thanks, Bart
 

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I know when an external pump starts to plug, or go bad, you can air in you fuel lines. I never had an internal pump do this, but I suppose it could happen.
An easy way to test it, is to take the line off the TBI, and run the line into a gas can. Have someone work the key, and watch the gas flow. After it runs steady and clear after the lines fill after the bleeding, but then gets eratic and you can see air bubbles in the gas, the pump is either partially plugged, or going bad. Do this after the truck has been warmed up, and acting up. Make sure you bleed the pressure off the line, before removing it. I pumped almost a gallon out once, before I started getting air bubbles.
Always be careful with gas, and Good Luck
 

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check your fuel pressure, put an elcheapo gauge from the store inline with the inlet fuel line ...

also check your fuel pressure after the fuel pressure regulator, fpr's when damaged slowly close up...

i'd check if it has fuel first it sounds like the ignition is fine, unless the ecu is getting hot from a damaged coil or something perhaps..

:)


and as always check all grounds and power wires for corrosion /damage check the voltage of the alternator while running (should be around 14v) 12 off and 10 cranking
perhaps stress test the battery as well who knows what it could be
 

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Discussion Starter #7
the egr seems ok.....I checked pressure right before it enters TB. seemed ok.
I just took off the fuel filter and drained it and blew it out. Started it up and it runs fine at idle . Ran it for a few minutes and seems ok. I am about to take it for a spin and see. It will only take 2 or 3 miles to know if it is ok.

Where would the fuel pressure regulator be ?
 

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Should be next to the fuel filter. I'm trying to think what else causes that sort of problem...you can try unplugging the O2 sensor harness (under the fuel filter, red, black and white wires) and see if it changes the way it runs. It will run without the O2 sensor plugged in. Sometimes O2 sensors don't throw an error code when they stop working, or they send out such erratic readings that the ECU can't calculate fuel/air ratios right. It's tough to say from here. Could be injectors, MAF sensor, throttle position sensor, O2 sensor, carbon clogging the EGR valve and associated passages in the intake, or an electrical gremlin such a an intermittent relay problem or a wire rubbing the body under the carpet.
 
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