I replaced the fuel filter, plugs, Distributor, rotor. I also cleaned the Mass Airflow sensor with electronic cleaner. I have used octane booster and that does not help a bit. I mostly use 92 octane fuel and it seems to ping a lot less with that fuel. Could it be a timing issue? or a bad knock sensor?
Timing should be set by the PCM. So you cant adjust the timing. However if you have a faulty knock sensor the PCM cant tell the proper time to fire. The knock sensor picks up on ignition ping and adjust the time to send spark to the plugs.. Other causes of ping can be the engine temp, faulty EGR or the engine can be to lean.
Thank you for the response. Could the knock sensor or EGR value be bad and the computer not store any trouble codes? No DTCs are stored. TIA!
They can but it doesnt happen often. Before you start spending money, take off the timing cover. Put the enginne at #1 TDC. Make sure the cam and crank are still alligned, alsi check if the chain is loose. A good chain would have very little slack. If it has alote of slack, change it and the gears. Make sure you keep it in time. I can get you a diagram for the timing marks if you need.
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SOURCE: 1997 gms 1500 with 5.7.
I had an Oldsmobile that was doing the same thing and I also replaced map sensor,crank sensor, cam sensor, electronic module, and many more items. Even put it on a computer scanner and it said that all systems checked out ready to start and run. (and it woudn't even start then unless I primed it)I had done this before I replaced everything. Finally a friend of mine (who was helping me diagnosis this problem and had his on automotive shop)said well the only thing left is the computor and after replacing it never had anymore problems. Hope this information helps.
Former mechanic
Robert
SOURCE: 99 gmc no power when passing or climbing
It could be electric fuel pump stall. The pump isn't pumping fuel fast enough. This model may have a inline fuel filter before the fuel pump as well that might need replacing.
SOURCE: 99 gmc no power when passing or climbing
It could be the cat. it sounds like this could be your problem
SOURCE: 1997 GMC TRUCK IS MISSING AT ACCELERATION
timing chain is streched replace chain and gear set
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