ok 99 2.5 5spd went to change timing belt today just bought the truck its got 150k on it not sure if it had ever been changed. Anyway couldn't get crank pulley off belt looked good anyway decided to wait till another day. Put the mark on crank @ TC on timing marks ,lined cam triangle to triangle,and oil pump diamond to diamond tightend up the belet tensionor and fired her up.
Purred like a kitten, took her down the road did real goo till i switched on the AC it started pinging and skipping,turned off ac and it continued running like crap. Help please Ranger guru's

 

Just something to think about. Are you sure that the anti freeze is completely full? I know man ran fine down the after I changed my belt then all of the sudden it started to run real bad kinda like what you are talking about. I figured out that it wanted more antifreeze in it. One of the few times that I have really messed up.