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Off idle stumble/hesitation, Intake backfire @ WOT
I'm stumped at the moment. I am trying to troubleshoot this problem but have hit a road block on where to turn next. Car idles smooth, drives fine but when you hit the throttle at idle it hesitates then revs fine. If you go WOT off idle it backfires through the intake once. While cruising, going WOT it will backfire once through the intake and appear to run fine. I've attached a log of a run and it looks like the left side leans out. Rec #'s 4492,5328 & 5754 are just before it backfires when going WOT on the freeway. At the end of the file, 3-4 times at idle I hit the throttle and it hesitates. What I have tried so far is plugs, checked wires, opti is new but not replaced for this problem, fuel pressure checks out, compression looks good (within 10 psi) and I have checked for vacuum leaks and cannot find any. This is the LT1 in my 69. All emissions deleted, mostly stock tune from a Corvette. If anyone has time and can look at the log and give me some more suggestions I would appreciate it.
Well, I seem to have finally figured, well fixed at least, my troubles. After rechecking everything mechanical electrical I wet back to the tune. I had tried several different F-body bins and all resulted in the same hesitation/backfire trouble. The PCM I have came from a 94 Vette with the $EEB file but I could never get it to work because I didn't have the CCM. But, after downloading the most recent Tunercat I saw they added a option "Data stream fuel enable". So I reloaded my original tune with that option unchecked and low and behold it worked. I've read that loading the different bins shouldn't matter but for what ever reason mine seems to like the $EEB tune. Go figure.