rabrooks

2009 Z06, LS7 AI 280 heads, RPM B3 cam, BTR springs, factory intake and TB, Halltech 103 CAI, LG Headers, Dewitts rad, and Fluidine 2 pass oil cooler,

The engine has 3000 miles on the upgrades in a different car. I purchased it, installed it in my car, had it tuned.

The problem: Under load, the engine hesitates as if it has a bad plug or plug wire. as the rpms increase, the hesitation goes away and strong power comes on. I changed plugs to a known good set. The problem persists. The plug wires are new. I didn't swap any plug wires.

When at the track, exiting a turn in third gear at a certain rpm, I get this hesitation. as the car speeds up the bad plug (hypothetical) starts working. Then the car has great power.

I can prevent the hesitation by downshifting into second before getting back on the throttle. The rpm is higher in the lower gear. It sort of reminds me of clearing out a rich running engine, then it runs good until it loads up again.

I have heard of a bent push rod causing this and the tune may cause it.

Please help me find this hesitation. I think it has to do with the cam and how its tuned

sevinn

Do you have any way to datalog while this is happening?

rabrooks

Not yet, other than getting the tuner to ride with me with his computer, which I have done in the past

rabrooks

I should have mentioned the engine is a 2007 and the car is a 2009. I purchased used factory fuel rail and injectors. All seemed fine until I asked the tuner to idle the engine down and trim the fuel. It was rich. He mentioned that the fuel was very sensitive. He would set it and then it wanted to fluctuate more than he was used to seeing. We checked the 02 sensors and they seemed to be ok

tblu92

There is no way to accurately diagnose what is causing this issue without data logging your engine and recording exactly what's going on when you feel the hesitation----Otherwise all you are getting is a guess ---
A misfire will most always produce a misfire code P0300----But your issue seems more fuel related---Either a lean or rich condition when just going into "power enrichment mode"
It can be many things---LTFT's being too far off---wrongly scaled fuel injectors--Improperly located MAF------Not enough timing at ramp in ---Vacuum leak---
Its time to bite the bullet and take it to a reputable shop---who can data log and review your tune