To start, I have a low mileage M20 and at around 5k+ RPM, there is a noticeable rattling noise coming from the engine. It isn't too loud but it is still there. I can't really think of what it could be. The engine is strong and there are no other issues other than the noise. I changed the plugs the other day and it looks like there was a little detonation going on. I put in 1 step colder plugs to see if that helps.
Engine info:
65k miles
Maintenance up to date
Electric fan with lower temp thermostat and colder temp switch on radiator
Valves adjusted last year
Stock cats with triflo catback
No power steering pump
Some ideas i've tossed around:
Running lean in high RPMs due to weak fuel pump or FPR problem but the car drives fine and is strong so...yea.
Running lean do to timing being advanced too much.
Detonation due to poor gas.
Something mechanical in the head rattling...maybe the rocker retaining clips or something.
So anyone have any ideas? I'm scared to keep taking the RPMs that high with that noise.
Thanks
Engine info:
65k miles
Maintenance up to date
Electric fan with lower temp thermostat and colder temp switch on radiator
Valves adjusted last year
Stock cats with triflo catback
No power steering pump
Some ideas i've tossed around:
Running lean in high RPMs due to weak fuel pump or FPR problem but the car drives fine and is strong so...yea.
Running lean do to timing being advanced too much.
Detonation due to poor gas.
Something mechanical in the head rattling...maybe the rocker retaining clips or something.
So anyone have any ideas? I'm scared to keep taking the RPMs that high with that noise.
Thanks