Trying to help a friend with a 90 chevy p/u 350 . The problem is it will run fine for sometimes up to two weeks then start stumbling and barely run at all. It also sends a code 44( lean I think)and then later go back to runing good. To make a long story short he has replaced everything in the fuel system from the fuel pickup to the throttle body. In electrical, he has replaced every component including the computor and prom and oxy sensor $1250.00 worth. Any help with this would be appreciated.

 

maybe one of the places he gets his gas from has dirty tanks or waters the gas down.

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-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

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Thanks Tas, but he replaced the electric fuel pump and pickup and cleaned the tank out and it still did the same thing.

 

Check the wire loom that brings the wires up for the injectors. these could be bare and grounding out causing one of the injectors to fire wrong. Do the same with the wires for the O2 sensor. What about the IAC and TPS? Check thos wires too. Also Make sure that the MAP sensor is good and none of the wires are cut, stripped or touching anything that they shouldn't be. I can't think of any other possiblities if he has replaced the entire fuel system.

-Lars

 

EGR valve?? TBI gasket?? Sometimes, the wrong PCV valve will cause incorrect IAC operation.

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'92 Astro 350 TBI Edelbrock intake, MSD 6AL, 3.42's, 2.5" exhaust, Flowmaster 40 2 chamber, B&M 2nd stage shift kit, 255 60 R15 tires on AR-727's

 

I was talking about the gas stations tank not your friends truck tank

 

Thanks guys,I will relay the info.