Need some help to save my sanity I have a 98 Dodge Ram 1500 4 x 4 5.2 V8 ,130,000 miles . automatic tranny

Bought the truck about a month ago the issues I've been having since I bought it is it there is a lack of power. Most times when I floor the accelerator it just slowly gains speed it does not get up and go like it should. The truck idles fine the RPMs are normal when shifting into gear. Last night with my wife was driving it speedometer stopped working ABS light airbag light and check engine light came on, did some research here on the forums swapped out the transmission speed sensor check engine light and other lights are turned off prior to the swap other than the check engine light which shut off on the way home from getting the code read. Looked in the throttle body does not appear that I have a plenum problem what else could be the issue?

 

Clogged cat. What was the code from the check engine light?

 

I'd still look at doing the plenum and a tune up, you might surprise yourself. Also, 3 ways to check for a plugged cat:
1. Unplug forward o2 sensor and test drive. If it runs much better and has lot more power you either have a cat or o2 sensor problem
2. In neutral, attempt to rev up to around 4k (once it's warmed up mind you). If it doesn't really wanna go past the 3k mark, plugged cat.
3. Rubber mallet or hammer with a block of wood against the cat. Beat the crap out of it with 2 or 3 real good swings. If it's clogged you'll break up some of the crap inside. Can get you by for a little bit until you can buy a new cat or whatever.

 

The codes it threw are p0500 speed sensor, p0123 tps voltage high, the p0123 was not showing up when I posted the original post

 

Also and code 71

 

on the 98, the speed sensor is the one in the top of the rear diff.

Test the TPS.... either a volt meter, or scan tool should tell the tale. Analog meter works best.