Question about 1994 Chevrolet S-10

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Rpm bounces from 1500 to 500 and back again

Replaced: fuel pump (2/05) and filter (2/09), PCV valve (2/09), EGR valve (2/09); fuel pump output is up to spec, there aren't any codes to read and I don't know what to do next. Please advise I'm at my wits end.

Bob

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  • whooui Feb 27, 2009

    carhob, no it doesn't just do it at idle but the PU is subject to stalling at idle then unless I drop it into netural and rev the motor. During it's unnoticable when excelerating but at cruising I can feel the variations. It was recommended to check for holes or cracks between the air cleaner and the throttle body but the mechanic says I don't have any sensors in between that would registar or cause a false reading. The mechanic also checked/tested the idle control sensor and it well within specs.

  • carhob May 11, 2010

    could be fuel pressure reg.,faultyor dirty injectors,if you didnt do this yet ,iwould have inj. syst.cleaned by your mec.

  • carhob May 11, 2010

    does it do it only at idle

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I have the same problem with my 94 s10 4.3 cpi.... I have been told after replacing fuel filter; 3 sensors; cap, rotor, plugs & wires; spider injection assembly; and a coil (and i could have even left something out the list is so long), that it is probably the 02 sensor by the cat converter. If not that then my injectors are already bad...oh yeah plus I cleaned the EGR valve. Does this only happen to you after you vehicle warms up? cuz thats when it goes crazy for me.

Posted on Oct 03, 2010

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