fondigley

I just lifted the truck, put on bigger tires and did the take plate mod. in the last 2 weeks. On the way to Moab from Denver Friday night, my truck had some problems. Anyone, who has done that drive knows the mountain passes on I-70. Well about 45 minutes into the drive my check engine light came on and my tachometer wouldn't go past 2250. So I pulled over in Frisco and checked things out, tried to look for an auto parts store, but none were to be found. Turned the car off and let it rest. After about 15 minutes started it up and reved the engine, it seemed to be fine, I thought. Started driving some more, then it happened again, so I pulled over and decided to close the airbox up thinking the extra air from the deck plate mod. was messing with a sensor and restricting the engine. With the engine on and the tranny in park it reved all the way up like nothing was wrong. Started driving again and similar problem. But was past the big passes of the route and was able to drive at 70mph without a problem. While continuing on to Moab, my friend and I had been trying to think of what would be causing this. We thought computer problems of some sort, but what. Then he blurted out something about a restriction on the overdrive. At that second I hit the overdrive button and it turned off and the tach reved right up. From then on we were smooth sailing, but the CEL was still on. I didn't seem to have any other problems, just kept the OD off the rest of the trip. The trip back was much more pleasant and in the daylight.

Has anyone experienced this or know what this is?
Any suggestions to fix this or prevent this from happening?

I believe this is all transmssion related. I have been doing a lot of reading and it seems maybe a better cooler. It seems I need the OD on the intersate, so want to figure this out.

rimpainter.com

Have Autozone pull the code. Then do a search here on YT for the code list. We can help you from there.

I highly doubt this has anything to do with the deckplate mod unless you unplugged something or pulled on a wire too much. I am willing to bet you knocked something loose or failed to put something back on during the lift install process. Maybe the VSS, but that is pure speculation. Get that code.

fondigley

Plan to get the code, but the light isn't on anymore. Will there still be a code? Also I figured it wasn't the deck plate mod. when I switched the OD button off, so I opened the box up for the drive home from Moab.

Edit: I also read about getting the CEL code from Autozone last week, when my CEL popped on for a second, but then went off. Searched for overdrive posts before I posted and didn't find what I was looking for. We thought the tranny may have gotten too hot, but maybe not. Another friend I met in Moab, said it was probably caused from the bigger tires and lift making the engine work harder and that I should run with the overdrive off. Figure I should get some more expertise.

rimpainter.com

Yeah, the code should still be there. See what they come up with. Good luck!

Flamedx4

My guess would be a combination of both - tranny getting hotter and engine computer seeing throttle/air/fuel/roadspeed ratios way out of 'normal.'

Upgrade the tranny cooler and change the gears.

rimpainter.com

I thought tranny overtemp would trip the "AT Temp" light. Do you think there would be a CEL code too? Just curious.

Flamedx4

Never heard of an AT Temp light. Doesn't mean there isn't one though....
Best fix is install one of these:

fondigley

The AT temp light didn't come on, so really didn't think it was overheating, but after reading some posts thought that could be the issue. plan to hit the auto store after work.

fondigley

Just got the code: P 120 I am trying to find it on the net right now.