I had some transmission work done on my truck – mostly an leak and replacing the harness – and ever since then after it rains or if we have a heavy dew my truck does the following:
Driving from O to 49 miles an hour truck is fine, as soon as I hit 50 the truck starts surging and you can see the tachometer jumping from 2000 RPM to 2500 RPMs. I drive around 17 miles to work where my truck will sit for seven hours. On the way home the truck is fine. I find this to be more of a problem when the truck has sat for a day or two over the weekend without driving it. Sometimes the “check engine” light will come on, sometimes not.
I have taken it to two different places and neither one says they can find anything wrong with the truck. I have driven this truck for over 11 years and know it very well. There is something wrong, but what?
Well the light just flickers or rarely stays the whole trip. But all it says “Service Engine Soon”. I don’t mean to sound dumb, but how would I find out what the fault codes are?
Since you say the trouble only seems to happen when there is moisture in the air that usually indicates there is a electrical connection problem somewhere. It might help to clean the grounds under the hood to the chassis, engine, and especially the transmission if there are some to it. Reconnecting connectors to the transmission controller and other things under the hood may help also.
Thank you everyone for your comments. I did learn how to read the codes using a paperclip (how cool is that) and did them last night. The codes showed no problems at all, but then I remembered that it only happens when wet so as soon as it rains I will try them again. The truck has 298,000 miles and other than this problem it runs great. I will sure try the locking out the overdrive thank you for that suggestion. And Cougar I will take the truck in and asks them to do what you suggested. I really appreciate everyone’s comments.