Check engine light question.

[pitbulldell]

when i start up my truck it will idle fine for about a minute,then the rpm's goes up to bout 1500 and the check engine light will flash 3 times. if left to idle the rpm's will come down then the check engine light will flash 3xs then 6xs sometimes 5xs somtimes 8xs but always a combo of these numbers.it will stop flashin once i put it in drive. also the a/c will not blow cold when its doing this.

I stopped by two different autoparts stores and tried to get it scanned but they keep gettin communication errors when tryin to read it from under the dash.
I plan on takin it to my uncles shop and scan it from the port under the hood. Its just his shop is a hour and a half drive and in the mean time i thought you guys might be able to help.

 

[FexplorerV8]

Sounds like you have a misfire, as far as I know any time your check engine light flashes is because of a misfire and your a/c will not work. This happened on my Lincoln when I had 2 bad coils, also make sure your battery is making contact properly.

 

[pitbulldell]

I thought so to so i did a complete tune up. and its still doin it

 

[pitbulldell]

any one?

 

[gijoecam]

Sounds like you may have an early-build that's not an OBD-2 vehicle... IIRC, there were a few of them out there...

Have them use a machine that tests the EEC-IV systems... Like what they would use on a 94 Explorer. They should be able to pull the trouble codes and see what's happening. Give us the code numbers it pulls off the ECu and we'll go from there. Don't let them tell you what's broke, just get the DTC and call it good.

I suspect a sensor is dropping out of range and the engine is trying to compensate for it by defaulting to a base program. It won't run well, but it'll run.

-Joe