misfires between 4-5kish only

[dougmacho]

Need some help guys, misfires in 2nd and less in 3rd; it breaks up 4-5k then boosts fine. Replaced plugs and wires, then regapped plugs.....looks ok. Its the oddest thing, havent data logged since i don't have a pc.

It is tuned by Whalen speed and has most all bolts ons, ecmlink, fp68 w/ manifold, injectors fuel rail, braided fuel lines, aeromotive fuel filter and fpr, and fuel cell. I believe Whalen set the fpr higher than stock setting, it was 40 psi without the vacuum attached; i took it down to 37 and it made not difference to the misfires.

The car was tuned while the ac pulley was seizing up, actually shredded the belt; i'm wondering if this affects the tune since the ac belt is now off and there not more drag from it. Would appreciate any help.

 

[kron_jdd]

Boost leaks?

 

[GSTwithPSI]

Post a log.

 

[Breakerrr]

you said you replaced your plugs....and redid the gap. What was the gap You used? I had a similar issue and changing my gaps from .28 to .23 got rid of the misfire.

 

[G]

So was it misfiring before or after the tune?

 

[Breakerrr]

i do my own tuning so its hard to give my tuning process a difinitive completion date.. but for the ease of conversation...after

 

[G]

Was asking op.

 

[dougmacho]

The car was running perfect with the tune, fast forward a year later and the coolant temp sensor went bad. The coolant temp sensor went bad and fouled the plugs. Bought new plugs and gapped them the same as the tuner had installed, at .2 I believe.

Really wondering if it's somehow related to the ac belt being off, since it was tuned with the ac compressor bearing Att seized. Before when the turbo timer was on, the engine would die, now it's able to run until the timer runs out. No drag on the motor.