84conversion50

Ever since i bought the car the idle quality hasnt been great. 1993 pcm 93 style injection. 427w. The idle surges no matter how high or low i put it. It will idle fine until you dip the idle then it will never find itself and bounce back and forth. It has bright green injectors, im assuming 42lb, and what looks like the original stock maf. Will upgrading the maf to the larger sizes help anything for this issue. If a tune is the only way to fix it is there any places i can send the pcm out and have it flashed. We have 1 guy here but he is booked for months.

Derf00

Yes, 42# is bright green. I can't see that current build needing that large of an injector. 42 lb injectors assume 600HP at the crank at a standard 80% duty cycle. 28 or even 32 lb injectors should be max for that motor if you're pushing 400HP
https://www.deatschwerks.com/fuel-ca...tor-calculator

At 42 the PCM is probably having a helluva time trying to control the fuel trim enough value to maintain a steady idle. There's only so much the PCM can dial back or add to the the fuel trim.

Upgrading the MAF may help a but it's still the same story, overrated injectors for the application.

84conversion50

It dynod mid 500s a few years back without the meth kit thats on it now. Is a tune the only solution. If so is there someone that can make a chip based on engine information.