Last week engine light came on, started running rough and shifting a bit hard. Before i could take to my son to hook scanner to it light went out. A couple days later when I started in the morning the Brake Light & ABS light came on, ran real rough and would not idle, all power was off to everything but door locks. After a few miles and restarted it, it went back to normal. Did the same thing today. Any help would be greatly appreciated.

 

Hook the scanner to it. It stores codes when the light goes out.

 

The scanner didn't see the code but said the following items might not be working correctly. EGR Valve or it's solenoid, MAP sensor. Speed sensor, Rear sensor. Can any of these cause the problems I described. I installed an OEM Map sensor about 2 months ago.

 

You just contradicted yourself, the code reader did display some codes. Please list the codes, by number, and when they were displayed (KOEO, CM or KOER).

 

I didn't do the scanning. my son did and that what he told me. The scanner did not communicate with the truck while running but did while it was not. I guess it was the codes that printed out of the scanner he was telling me about. But he could not say for sure what was causing the problem.

 

Drove the truck to airport and back,150 miles each way this week, no problems. Just see on the mornings when the temp. is upper 30s and below that the problem occurs.

 

Check your battery cables.

 

It does it ever cold morning ( 35 and below) The break-light and ADS light are on. Now just the fan for the heat/ac will not work, sometimes the radio, speedometer, and electric windows don't. After about 5 miles of driving I stop and restart it, everything things work as usual. Any help would be greatly appreciated.

 

Check/clean the ground near the battery/starter relay. Do the same for the ground on the radiator support near the driver side headlight.

 

Thanks for the reply. Cleaned all ground connection this past weekend. Waiting on the next cold weather later this week to see if it worked.

 

Grounds didn't do it, so I started with replacing parts. Tried ABS sensor first. 15 degrees this morning and everything worked. Hope this is it. Thanks for all the feedback.

 

Well spoke to soon. It worked great the last few days with temp. in the teens and twenties. This morning it was 39, it started with a real rough idle, so I restarted it, this time idle good but then the ABS light & Break light came on again. No heater fan, speedometer, or power windows. After about 5 miles restarted back to normal. My son is convinced it is the computer. It was damp morning today and he thinks moisture is causing computer to cause this. Do yall think it is a possible cause.

 

The computer has nothing to do with your ABS and auxiliary power devices not working. You've got a wiring issue that needs to be addressed.

Start with your grounds. Double check all the body to frame, body to battery, and engine block to battery grounds.

 

OK.. few things you should know about your truck...
Both engine and transmission are controlled by the same computer.
Speed is a critical computer input for correct engine and transmission operation.
The rear axle sensor does double duty as the RABS and VSS(speed) sensor, but that signal goes through the PSOM module(speedo cluster) before going to the computer.

So the common denominator for all the symptoms you're having seems to be the VSS input though it appears you're also having some power issues so your problem may be more wiring related than with a particular sensor. And since this all comes together in the cab that may be a good place to start looking, maybe you have a chaffed wire, maybe the ignition switch is worn and intermittent, maybe there is a connector lose.

 

Thanks for the info. Will try and check those things out.