My 2001 ram 3500 hesitates and threatens to stall when accelerating from stop. Runs fine once it "catches " and gets up to speed. Had the throttle position sensor checked, that's not it. The check engine light is on, throwing emissions related codes. Any advice on what to check next?

 

What emissions related codes?

 

2 different oxygen sensors, "circuit voltage too high"
Also, the problem is getting worse, and yesterday while it was lagging and struggling to accelerate I heard some popping noises from under the hood. Not as loud as a backfire, and at random intervals. The truck seemed sure to stall completely, but after a few minutes it "caught" and took right off.

 

Might want to look into the plenum and see it you have oil pooling in the bottom.

http://www.hughesengines.com/Index/p...p?partid=27091

 

Try disconnecting the O2 sensors, and see if it runs any better.