capitalking Posted August 30, 2008 Share Posted August 30, 2008 was running fine...then slowly, acceleration in 2nd gear would lag and start to backfire under heavy acceleration. then, progressively in 3rd, and finally all gears. before i could accelerate slow and had no problem, but after 10 or so miles it got worse. any ideas? i couldnt find any vaccuum leaks, and that's about as far as i've gotten. Link to comment Share on other sites More sharing options...
Eagle Posted August 30, 2008 Share Posted August 30, 2008 Clogged catalytic converter will rob power Link to comment Share on other sites More sharing options...
capitalking Posted August 30, 2008 Author Share Posted August 30, 2008 the cat's been gone for years now. the truck sat for a number of years, so i wonder if maybe it had something in the fuel tank, and now it's surfaced and is catching in the fuel line? it's a new filter. Link to comment Share on other sites More sharing options...
maddzz1 Posted August 30, 2008 Share Posted August 30, 2008 Could also be the wires. Link to comment Share on other sites More sharing options...
capitalking Posted August 30, 2008 Author Share Posted August 30, 2008 has new wires, plugs, cap/rotor, fuel filter. checked all vac leaks. Link to comment Share on other sites More sharing options...
skitch Posted August 31, 2008 Share Posted August 31, 2008 timing? even though i would have to agree with your fuel comment to. mine did the same thing. even though it was pricey i ran high test fuel in it for a while then mid grade. and it seemed to clear up. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted August 31, 2008 Share Posted August 31, 2008 fuel pump failure, distributor isn't indexed properly and timing is off, perhaps a failing CPS maybe dirty injector or the filter is already clogged....unlikely though with those symptoms that's all I can think of. basically, a bad fuel pump which still puts out less than max PSI would work fine at lower RPM's, but when you got to running higher RPM's where more pressure is needed to fuel it faster, it cannot match the necessary output for your engine's needs. dizzy indexed properly...it may be off by one tooth. this could explain poor running and no acceleration...my 87 MJ with a 4.0 had the distributor off by one tooth, and it would idle PERFECT but you couldn't rev it above 1200 RPM..., where it would begin to pop and backfire...it would run up to around 1800 RPM then just kill itself. failing CPS would read poor signals and not keep up with the timing and therefor not spark at the necessary moments...subsequently, if your flywheel is missing any of the timing teeth, you will net the same result (bad flywheel = pull tranny) my bet is my second scenario is correct. did you do any dizzy work recently, or has it been done recently? Link to comment Share on other sites More sharing options...
capitalking Posted August 31, 2008 Author Share Posted August 31, 2008 nope, no work done recently. i have been driving it harder lately. instead of the average 8mi a day, i've been throwing some 100 mi and 65mph trips into it. funny, before i bought it (like 3 months ago) i test drove it, everything worked great. a/c, signals, no smoke, no leaks. nothing. within 2 weeks the alternator, upper radiator hose, thermo, and a/c comp all crapped out. but what do you expect from a $500 buy. body's straight, interiors straight, was running strong. Link to comment Share on other sites More sharing options...
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