idle problem and diagnostic says ...1992 gmc incomplete

[madman92ty]

check it out guys my 92 ty has a shitty idle,,, at start up its all good but when it idles down thats were the prob beggins it stays like at 1000 rpm then drops to like 500 and goes back up and down ,,, and sometimes it just idles down and shuts off,,,, it does this when it wants too i can be driveing and let go of the gas and its fine or i can let the gas go and it just idles so low it turns off or it just does that decrease and increase idle.. me and my buddy hooked it up to the diagnostic tool and it reads "1992 gmc incomplete " (snap on diagnostic tool )so basically it just wont read the computer ... do i need a new one,,, OH GOD DONT TELL ME I NEED A NEW ONE.... i say i need a bottle of "UR TRUCK IS F'd UP" n e help would be nice thnaks in advance...

 

[Mad Mike]

I have a ECM for sale if you need one.

 

[SeattleSy#1255]

wow man hold on for a sec:

did you change all the ignition things such as wires, plugs, cap/rotor?

i'd check what chip you have in it as well, thats real important.

I don't think you can conclude you need a new ECM with just a crappy idle. try a few things. I mean your injecters could be dirty, your fuel pressure messed up. Hold off on assuming your ECM is toast.

try the basics first then let us know.

 

[midnightbluS10]

It says 1992 GMC incomplete b/c that's how it left the GMC plant. The VIN dictates that info, as well IIRC

 

[madman92ty]

ive changed ,,, plugs,wires,cap& rotor, pcv,fuel pump,fuel filter,and a complete tune-up they say maybe the TPS?

 

[dgoodhue]

Re: idle problem and diagnostic says ...1992 gmc incomplete

I would look into cleaning out the IAC circuit below the Throttle Body (this is what control your idle) Its gets clogged up, with carbon deposts. You will need some new gaskets.

 

[ericguy320]

will it go to base idle when you jumper a and b on the aldl?

 

[danny]

when you are setting up the scanner with your info something wasn't installed correctly. i have the same scan tool and had this before. if i remember right i kept entering the wrong tranny. when it asks for trans i THINK i had to scroll till it came up awd turbo or something with turbo in it. my scanner is at work so i can't look to verify. just double check the stuff you entered.

 

[gmcturbo]

most scan tools ive hooked to my ty say that. the snap on vantage and matco determinator to name 2.. i would do a tune up..