Bad tuning or a mechanical problem?

[BlueOvalStangGT]

Its been SO long since I have had a good running car so I kinda forgot what I need to do here. I FINALLY fixed my timing-ECT problem with a new computer....so now its time to start REALLY tuning. Heres my problem:

Right now im running a pretty much stock J4J1 with a few scalar changes for 42 # injectors, a generic 42# MAF curve, and a few minor scalor changes. If I start the car, it will idle pretty well until I touch the gas. Then the car will surge and either catch itself or stall. Also, when I get on it it will kinda miss/studder and sometimes pop. Basically the idle thing is what I want to fix first....how should I start? Should I tune with the tweecer or could it be a mechanical thing like the IAC or TB?

 

[BlueOvalStangGT]

Bump

 

[cbarr300]

I had problems that sound similar to yours. It ended up being my MAF curve. What kind of MAF do you have?

A bad maf curve can cause all kinds of bucking, jerking, stalling, etc. Also, befor you try to adjust the maf curve I'd suggest that you clean the maf with some contact cleaner first.

My guess is that once u mash the go fast pedal it dumps too much fuel in and becomes rich. Maybe lean the mixture in the lower end of ur maf curve and see if that fixes anything. A wideband realllly helps for this.

I'm sure more knowledgeable peeps will chime in

good luck

 

[final5-0]

Keven

Just off the top of my mind ....................

offsets for 42's
you may need to cut minimum pulse width down a bit
you may need to cut back some fuel in startup table
you may need to lean back the first 4 to 6 maf points a bit

Lots of the guys on the Tweecer support site run 42's
so
go over there for more detail
than
the almost useless info I am trying to provide

At idle, what does your K's or wb have to say

Grady