Please Read all before you answer.....I tried everything I can think of.

Here's the facts: 05 LS2 GTO 6 Speed New GM Crate Motor 6000 miles

Only Mods are Cold Air Intake and Muffler Delete Stock Tune.

Swapped injectors from cylinder to cylinder, All New Coils, New Wires,

Tr55 Plugs gapped to .057", New Delco O2 sensors, Valve springs are

good, Push rods not bent, No bent valves, Leak down test is perfect,

perfect compression.

Car will miss heavily at around 1900 to 2200 rpm's on cylinders 5 and 8

only verified with HP Tuners scan. Doesn't really feel like it really and

really can't hear it in the exhaust note. Car doesn't lug or have any lack

of power??.

All the plugs look great and there is no Knock. Im thinking its gotta be

electrical? Car does Idle a little rough at times though...maybe im

paranoid though.


Here is what my possible next steps are:

1.Replace the Crank Position sensor and perform a case learn?

2. Cam Sensor??

3. Any Ideas or suggestions please feel free to share....????

 

After reading through hundreds of threads ect...

Driveline Vibration IE: Flywheel / driveshaft ect.... MIGHT be a good bet because it

only does it at the certain RPM's 1800 to 2200ish. Does that sound logical???

 

Up^^^

 

So it show a misfire but dont feel like it misfire. What will it do if it in drive and you power brake it at the rpm u have the problem?

 

Update:


Thought I would post the results for future searches.


Installed Cam sensor and went 70 miles in the RPM range that is was throwing the code.....and the code did not come back. Before the code would pop up every 3 to 4 seconds while cruising in that range.

Hopefully this was it....crossing fingers.

 

Thats good you found something, keep us updated after some more miles are on to verify.

 

Good new!

 

Final Update:

The code did start coming back after 150 miles but not as much. I stopped at a GM dealer and had them perform a quick crank sensor relearn with there Tech II.

Low and behold the symptoms are totally gone. We couldnt get HP Tuners to perform the relearn for some reason?