I rebuilt my engine recently. It has run great for 1200 miles and now all of a sudden I have what sounds like pre detonation knock. It only occurs when accelerating. I have added some octane boost to the fuel but no change. And I have no trouble codes. Just to do something I changed the knock sensor but no improvement. Why would it run for 1200 miles and then start knocking? Any suggestions appreciated.
2001 Montana engine knock question.
- Thread starter MontGuy
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two guesses, EGR and crank shaft position sensor. If you have a 3.1/3.4 some tests you can perform
http://easyautodiagnostics.com/gm/3.1L-3.4L/index-of-articles-1
http://easyautodiagnostics.com/gm/3.1L-3.4L/index-of-articles-1
Sorry for the long delay in replying. I never got any engine codes so finally took it took it to a shop I am familiar with. Turns out I had an exhaust leak at the rear manifold and what I was hearing was exhaust noise (total surprise to me). But a new O gasket and 1 hour of their labor and the problem is gone. Sounds great again.