Ok I got a 91 ford ranger 5 speed with the 2.3.. I've replaced ecm, tps, spark plugs, wires, fuel filter, pcv valve, both coil packs and that's it I think.. but when I got the truck it was getin 25 mpg and runnin fine then all the sudden it got 18 mpg and runnin like crap. It hesitates and when you hold the throttle a certain way it sputers. Now when I unplug the tps it runs fine just idles high but still didn't change the mpg to much.. what could the problem be..

 

clean the IACV if you have one.

 

What's that and where would it be located.. also I meant to say it smells like it runs rich

 

Idle Air Control Valve. should be on the throttle body somewhere. looks like this http://www.autozone.com/autozone/par...78837_11735_0_ spray some electrical cleaner in there, NOT WD40, it will gum up.

edit: since you replaced the TPS, it should have a warranty correct? if so, go get a new one with your warranty.

 

Ok I will try it

 

clean the MAF sensor while you're at it.

 

When was the timing belt last changed.
If it's old and stretched it may have jumped a tooth.

 

Idk I thought of that but it don't aqlways do it. Sometimes you caN go down the rd and it runnin like crap one min then all the sudden it clears up. Seems like something electronic

 

when my IACV is cold, it causes a hesitation and it sputters, then pulls out of it. after it warms up, its fine. I'm to cheap to replace mine, so I spray it like once a week with electronic cleaner. at first I thought it was my brand new TPS, so I had it replaced under warranty, but that wasn't the problem. a jump in timing is usually something more serious imo, then just a sputter and hesitation that goes away.