I Got A 1993 4 Cyl. P/u 22-re , Stck Shift, 290000 Miles. The Idel Keeps Reving Up And Down Also The Exhaust Smells Foul, This Is Been Going On For A Week Now , It Did Stop For A Day And The Idel Was Normal But Its Doing It Again,
I Do Not Have Shop Manual, Can Someone Help Thanx

 

You have a messed up cat. converter. The reason it is revving up and down (by the way the technical name for that is "hunting") is because the 02 sensor is trying to compensate. Go have the cat. replaced and you'll be good to go.

 

Does it happen only when you step on the break with the A/C on? That happened to mine for seemingly no reason. I just adjusted the idle down and it runs fine now. The exhaust though, I don't know. Cat clogged up? Bad oxygen sensor? Bad oxygen sensor clogged the cat up?
I am working on putting the service manual for the '93 online with all my .pdf files. You can find it here http://personal.utulsa.edu/~nathan-b...fsm/index.html . The engine section is complete, you can look in that. The troubleshooting charts seem pretty handy, though they are kinda tricky at first. Good luck

 

Aw heck, I took too long to post Oh well.