robertbartsch

I put H/C in the car a few years back (2002) and no issues so far.

About one year ago I had my PCM replaced. I used LS1Edit to tune the car after a factory fresh PCM was installed by GM and it ran great until recently.

Now it stumbles a tad before it hits 3K RPM and also it idles ruff when warm. The idle problem seems worse when the weather is hot "and or" the AC is on. I've filled the tank at different gas stations and I don't believe I got bad gas.

I pulled and replaced the plugs last weekend. No fix. I'll look for PCM codes with a code reader tonight but I just had an NYS inspection so thrown codes would have been an issue if they were present; right?

Are there any obvious things I should consider? Should I re-check the plug wires; they are TR units that look in great shape - about 1.5 years old. The stock fuel filter is still on the car.

The A/F controls are mostly stock including factory injectors, factory air pump, accept I do have an aftermarket MAF, ported TB, air lid, LS6 intake, drilled block-off gaskets on header check valves, oil catch can.

The oil catch can is dry as a bone so I doubt the top of the engine and injectors are coated with crankcase oil.

I have replaced the cam sensor twice since the H/C swap. It went bad again one year ago. I'm not sure why. Is this metal flakes from the cam wearing getting in the sensor? The car starts right up so I don't beleive the cam sesnor is bad again.

I also replaced the crank position sensor one year ago after the new PCM. The PCM was not recalibrated for the new crank position sensor. Is this a possible source of trouble?

It acts like a bad plug or plug wire issue but I doubt it.

Thanks...

ZL1Killa

iTrader: (17)

ok well when the AC is on the car commands more Air flow.... so log your Desired Airflow vs your actual and compare to your IAC steps... you probably need to adjust it. or make your TB blade open more or drill the whole in it bigger

now I have efi live so idk about ls1edit

robertbartsch

Car also runs ruff with AC off. TB has been drilled a tad in 2001.

ZL1Killa

iTrader: (17)

worse with the AC off or on?

log your airflow values...don't know how to tell you to do it in ls1edit

brickhoss

iTrader: (1)

You might consider the fact of the new 10% ethanol gas mixture that is now mandated... Not sure, but I know it has been an issue on my tuned WRX... If you're tuned on good fuel, it can definitely make a difference w/ things such as studdering/running crappy.

Not sure if its a federal mandate on the 10%, but i know that ever since it started in MD, my car has been much worse, and could probably use a retune

ZL1Killa

iTrader: (17)

damn.... i'm going to hate the day that Nc switches, i'm enjoying my 93 octane right now

Bad30th

iTrader: (13)

Swapped/checked O2 sensors ?

Rob (Bad30th)

robertbartsch

New 02 sensors 6 months ago. Corn gas was mandated recently in NY and my car hates this cra*p. It cost more $ and delivers less mileage too.

No CPU codes.

Is it a bad idea to clean off intake senors with brake cleaner spray? Just a thought but, since I have no codes, this is probably a bad idea; right?

robertbartsch

How about the non-calibration of the crank sensor. Is this a potential problem or if calibration was "off" when the crank sensor was initially installed one year ago would the engine have run crappy then and not just recently?

Thanks...