rickwolhoy
Newbie
Hey all, I've been grappling with a random misfire for a while now. I have a 2000 chevy tahoe z71 with the 5.7 vortec, currently at 322k miles. About a year ago I had a bad misfire at idle on cylinder 3 and after a leak down test I found that the exhaust valve was leaking way beyond spec. I purchased new 062 heads and installed them. After installation the misfire on cylinder 3 was gone but now i am getting a random weird misfire after warmup along with a rough idle. It's only 1 or 2 misfires here and there and it's not on any particular cylinder. I started throwing parts at it but that is not getting me anywhere. I also have slightly high LTFT on Bank 1, about 10-12 percent after warmup. Bank 1 LTFT stays below 10 and somtimes goes into the negative but only slighty 1-2 percent. Any help would be very much appreciative! Below is a list of what I have done to try to get ride of this misfire. I should also note that I have no SES light on and no diagnostic codes. I do have a bluetooth scanner with the dash command app so I can read a lot of information. PLEASE PLEASE I love this truck too mcuh and I plan on doing a minor restoration and keeping it forever.
-062 heads from jegs
-distributor is about a year old
-new cap and rotor
-plug wires about a year old
-new bosch iridium plugs
-new denso upstream 02 sensors
-spyder injector about a year old
-Delphi MAF about a year old
-All new top end gaskets
-new timing chain set
-I have smoke tested it for vacuum leak and I found the intake was leakign around the throttle body and I took care of that and smoke test again and could not find any vacuum leak at all
-gm fuel pump about a year old/ fuel pressure at 60 psi
-062 heads from jegs
-distributor is about a year old
-new cap and rotor
-plug wires about a year old
-new bosch iridium plugs
-new denso upstream 02 sensors
-spyder injector about a year old
-Delphi MAF about a year old
-All new top end gaskets
-new timing chain set
-I have smoke tested it for vacuum leak and I found the intake was leakign around the throttle body and I took care of that and smoke test again and could not find any vacuum leak at all
-gm fuel pump about a year old/ fuel pressure at 60 psi
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