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backfire in airbox??????????

bigredjeep777

NAXJA Forum User
Location
oregon
i have an 87 jeep cherokee 4.0. and it ran great ontill i washed the engine and ruined the (tps) i replaced and it ran fine. a few days after that when i hit 2000 rpm like up a hill or any load really it bangs in what sounds like the air box its a pop pop pop and the engine misses and loses some power. but only around 2000 and when i put a load like a hill or something any ideas on what would make it do this????????? It has had a good tune up plugs wires cap all checked and good tps good aic good.
 
Since it only happens at a particular RPM I would re-check the TPS adjustment first since it was newly installed. Just MHO. 5-90 or Ecomike would be much better suited to answer this particular type question.
 
That 2000 RPM buck, bump or bang as you call it, is often a lean motor. Sometimes the O2 sensor, sometimes something else. It can also come from the timing, usually either the TPS or the distributor (especially on an 87).
 
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