1996 Chevy pickup 5.7 issues

Asked by Jan 29, 2016 at 07:04 AM

Question type: Maintenance & Repair

My truck cranks and runs fine until about 50 + mph
and hold. Then it starts to feel like its missing and
sometimes pops aka back fires. I can make it
really act up by downshifting bringing rpm up to
where it throws a code p0301. I've changed
wires,plugs,cap,rotor,fuel injection assembly,fuel
pump,crankshaft sensor. The engine has less then
20,000 miles on it but sat off and on for about a
year. I've put every chemical in it thinking it may be
carbon build up but nothing. I've sprayed the whole
motor with starter fluid looking for vacuum leak
but idles smooth.

1 Answer

74,715

Possible causes po301...> - Faulty spark plug 1 - Clogged or faulty fuel injector 1 - Faulty ignition coil 1 - Fuel injector 1 harness is open or shorted - Fuel injector 1 circuit poor electrical connection - Ignition coil 1 harness is open or shorted - Ignition coil 1 circuit poor electrical connection - Insufficient cylinder 1 compression - Incorrect fuel pressure - Intake air leak Tech notes The P0301 code means that the cylinder 1 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 1. If the problem persist more tests needs to be done to diagnose problem, see "Possible Causes................> Besides all this, I would also have the pick-up coil & the ignition control module tested that are located under the distributor cap. One other thing is to make sure the EGR valve is not all carbon up and is closing properly.

Your Answer

Chevrolet Experts

  • #1
    Tom Demyan
    Reputation
    23,460
  • #2
    Rowefast
    Reputation
    16,820
  • #3
    John Saffrahn
    Reputation
    16,160
View All

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.