Zman17 I'm not here to make your upset. I did look at your link. I'm going to try it today. Sorry for making your upset man.

 

LOL, Dude... I'm not upset.

 

Just did the key trick. Code 12 and 21. From my intrepid days I remember code 12 as battery removed with in the last 50 key cycles, and code 21 a bad oxygen sensor. Surely a bad oxygen sensor wouldn't cause my problem right?

 

I'm thinking your plenum gasket is blown,cat is clogged and o2 sensor is bad. If those issues exist, the engine is seriously lugging/under powered, and it is possible that the up shifting and down shifting can be a result.

 

How do I tell if the gasket is blown? Also what about the code 12?

 

My mechanic came over and looked at it and said the plenum gasket is good. He said I do need to replace the oxygen sensor asap or it will clog up my cat. Where is the output speed sensor located and which side?

 

You can do this to check the gasket, which IMHO is useless http://dodgeram.info/tsb/2000/09-05-00.htm . Or remove the TB, get a small extendable mirror and flashlight, and look around the entire interior of the intake manifold. You will see oil pooling and maybe even gasket material if it's blown. To check the cat, unplug the pre cat o2, unscrew it from the pipe, plug it back in leaving it hanging. Take it for a drive and see how it runs.

 

Thanks man. Where is the output sensor location?

 

The rear most sensor on the driver side of the tranny. One more thing! Put ALL the info about your truck in your sig. Make, model,year, eng size, 2 or 4wd, mods you have done (if any) etc......

 

Thanks!