cowlover556

iTrader: (1)

My NB2 is having an intermittent misfire at both cruise and under acceleration. AFR gauge will spike to 15.5-16 from 14.5 under cruise while the misfire is happening. Ive changed the coils, wires, sparkplugs and the fuel filter.

The lean condition leads me to believe that theres something wrong with the fuel system, I was hoping mt.net had some tips on how I can test the fuel pump and/or the injectors.

Car specs are:

MS3 Pro
FM turbo with gt2560
AEM FP
ID1050x injectors
GM Flex Fuel sensor

Thanks in advanced!

cowlover556

iTrader: (1)

Should add: Unfortunately my NB is my only car, thus I'm looking for ways to test fuel stuff that I am unfamiliar with (ie, does MS have a diagnostics mode?) as I cant have the car out of service for too long

curly

iTrader: (25)

Post a log of the misfire happening and your current tune

Skamba

When you have a misfire, the lambda sensor will always show lean as there is unburnt oxygen in the exhaust. It does not necessarily have to have to do with fueling.

cowlover556

iTrader: (1)

What else should I be looking for?

curly

iTrader: (25)

Well I’m looking for a log and tune, if that helps.

cowlover556

iTrader: (1)

Got a chance to drive the car. Tune and 2 logs included. The shorter log is at idle when I parked. Car started shaking and AFRs spiked, all new symptoms

curly

iTrader: (25)

I don't even know where to start.

Your fuel table looks horrible, and all I can see from the shorter log is that you need to disable idle VE and tune your fuel table in the idle cells before enabling it again. You need about 15% more fuel at idle during that log, so ~1150rpm and ~36kpa. Your idle seems ~100rpm high, and then you're also adding 150rpm when your fan is on, definitely could try some lower rpms there.

The second log has a MASSIVE issue with the rpm signal. It's never stable. If that's the main issue you're posting here for, the $0 test is closing your crank trigger gap, then I'd start looking at cam and crank sensors.

cowlover556

iTrader: (1)

Oof that's not what I wanted to hear after spending nearly 1200$ at a reputable tuner here in SoCal. The main reason was for the stutter during cruise (first log). Second log issues just showed up today

curly

iTrader: (25)

start with the items I mentioned with the misfire. It may solve other issues, you never know.

cowlover556

iTrader: (1)

I replaced both and the misfire is still present. I think Im going to be pulling the injectors and sending them to ID to be tested/cleaned