98 6.5L not shifting properly

[cchaney]

I have a 98 2500 that when started runs fine and starts easaly. When driving the truck it is slugish and will only shift from first to second then when thtottle is released it acts like the truck has been shifted to nuetral and the guages go crazy. I took the truck to the local dealer and was told the problem was the ECM so I replaced it and can not get it to relearn and start with a new ECM. I have a feel the problem is the engine speed sensor(the sensor in the distributer hole) or the optical speed sensor on the transmission. The truck has a lot of miles on it but still runs very well it just will not drive well. Any sugestions on where to start would be greatly appreciated.

[racer55]

Is the security light staying on while you try to start the truck?

Do a google search for security passlock relearn procedure.

[cchaney]

No security light truck runs great in park motor is strong, and every thing is working well it just does not drive.....I was think it might have something to do with the speed sensor/oil pump drive the is mounted in the "distributor" hole.

[racer55]

A 98 should not have that sensor,it is from older mechanical IP engines.

The CPS/OPS are the electonic IP's ECM tach while the alternator feeds the tach on the dash.

The trans does not have an optical sensor,it should have a speed sensor like the CPS in the trans.

Odd dash behavior sounds like ground troubles,clean/repair the common grounds at the rear of the intake near your dist hole transducer.

[JohnC]

Check the power at the trans and/or instrument fuse. Separate circuit from the (often faulty) ignition switch, causes shifting problems.

[Warren96]

With driving problems like this it must have a code stored. What are the codes?