Rough idle, and brief drop in RPM
When I first joined up on this site I had a rough idol and drop in rpm problem and it was suggested that I clean my throttle body and my MAF sensor, it took awhile for me to get around to it but I cleaned the throttle body and the MAF sensor, I also changed my plugs to Bosch Platinum+4's. It is odd but sometimes it will idle rough then other times it wont and run smooth, as for the dip in the RPM's I originally reported that it would do it about every 40 seconds, after the cleaning it will drop in RPM and shudder but not as often as before. Any other suggestions?
06 Colorado 3.5, with recently replaced head for valve issue.