I just bought a '90 1500 5.7l with a stage 2 or 3 chip in it. It also has a K&N, exhaust and an after market coil. It runs great however it throws a code(service engine soon light) every now and then. I also notice that it has a small miss at idle and chugs sometimes in OD. I had another '90 that had the stage 1 chip and never had any of these symptoms. Anyone has any experience with this?

The computer usually stores a trouble code when the Services Engine Soon light comes on while driving. Have you checked for trouble codes?

Here are some web sites with the basics on retrieving codes without a scan tool or code reader.

Poor drawing of ALDL but ok instruction + codes
http://www.cfm-tech.com/gm_tbi_trouble_codes.htm

OBDI terminal identification
http://robertpowersmotorsports.freeservers.com/images/ALDL_plug.jpg

OBDI illustration and instructions
http://www.troublecodes.net/GM/

Let us know what code or codes you find.

Yeah I'd be interested in hearing what the problem is. I'm looking at getting the Hypertech for my 94. Does your truck have a different cam or anything?

I am running the same (stage 2) chip level on my 91 and have no issue with codes. I have shortie headers, K&N filter, 180 degreee T/stat, MSD 6AL soark unit, and a TBI spacer installed.

Yeah I'd be interested in hearing what the problem is. I'm looking at getting the Hypertech for my 94. Does your truck have a different cam or anything?

No, the motor is completely stock. Don't get me wrong it runs great. It just has a slight stumble while sitting in drive idling.

Question: With the chip not being stock anymore will it still be able to read codes correctly?

Question: With the chip not being stock anymore will it still be able to read codes correctly? Yes, the codes are generated by the ECM, and reading them is the same.

i just put a hypertech in my 96 and the check engine comes on and off once in awhile but i know what it is already but i run a 160 thermostat and it still runs like no tomorrow ever since i go the hypertech its runs better i out ran a hemi last night i was proud of my v6