Engine 'clicking' at high rpms
 

Hey ya'll, I have a 2003 Chevy Blazer ZR2 with 136,900 miles on her. I recently noticed that there is a very loud click that is only apparent when you are accelerating above 4,000 RPM. The click gets more frequent and louder the higher the RPM goes. The engine light was also on. So now we put in an OB2 sensor and scanned a bad crank sensor. I just recently replaced the crank sensor and now not only is the code back, there is still clicking and there is the code for 2 random misfires. The engine light now will also start blinking at random points (Usually above 30 mph). What the hell do I do now, where do I even start?:icon_emm:

IMO at 4 tho rpms you should be at the max for rpms for a stock engine, you have a engine that has 136,900 miles on it so you have wear here and there anyways, You are prob floating valves, rattling rods ect and more than likely doing major damage. From my understanding that when a crank sensor is replaced or disturbed it has to go thu a relearn process with a capable scanner - IMHO keep over revving it and you will not have to worry about the tick or the miss fire too long as you will be looking for a engine :icon_slap:

Sounds like you have knocked the bearings out of this engine by beating it to death.

Seriously, start by taking it to someone who knows how to listen for a rod knock. Loose bearings can cause false misfire codes to be set. I know this very well from my own vehicle.

@Lesmyer @odat I solved the problem, had nothing to do with any of that, just bought a bad crank sensor.

Still STOP running it above 4K :)

I don't suppose you bothered to do a crankshaft sensor relearn after disturbing the sensor. It's a really simple device that is definitely not prone to failures and cannot be the cause of an engine miss, but if a crank relearn is not done after disturbing it in any way then all bets are off for correct misfire detection (you will observe false misfires).

I really doubt if your problems are solved, but if so then great. Just don't want others to think replacing crank sensors willy-nilly is a good strategy.

I think I may have foolishly understated what I had done. Both crank sensors were giving me a problem so after a long amount of searching I found something... a service bulletin. The crank sensor apparently goes into position too deep and there was a shim kit that was made in order to push them back. The new crank sensor was unaffected by the shim kit, but the old one stopped the misfire and now my engine is running just fine, along with the engine light having gone off. Sorry for the confusion.