Hey so after reading many threads on this site I decided to join and start my own. I have a 1999 ram 2500 with a body and computer from a 2000. I have pulled the cat and running dual exhaust but had some O2 sensor issues so I welded bungs in one of the exhaust runs and re-installed new O2 sensors. Now I’m still getting O2 sensor circuit high voltage, bank 1 sensor 1 CEL. I’m also getting a little black smoke out of the exhaust, I know some should be expected with no cat but how much? The worst problem is surging rpms at mid throttle, some days are much worse than others. Low rpms are steady and same at WOT. It almost seems like it’s going to stall out completely sometimes. Here’s a list of what I’ve done/replaced, any help is greatly appreciated!
-New O2 sensors front and rear
-new throttle position sensor
-new crankshaft position sensor
-new brake pedal switch
-checked psv on valve cover drivers side, seems in rough shape, going to get a new one

 

It's running rich, which it really shouldn't, even with no cat.

Need to plug in with a scanner, and see what you are getting from the O2 sensor. You likely have a wiring issue.

 

Can I test the wiring at the plug with a multimeter? Or did you mean a wiring issue elsewhere? It didn’t do this before I pulled the cat.

 

Did you pinch a wire somewhere? Should be able to test right at the connector. Should be 12 volts on one wire, 5 volts on another, other two shouldn't show any voltage. (one is just a ground, the other is signal return to the PCM.)

I suspect though, that the 12 volts will only be there for a few seconds at key-on, unless the engine is actually running.

 

I very well could have when I replaced the transmission in February. I’ll try that out, thanks.

 

Oh. Yeah. Replaced the trans? You will want to have a look at the crankshaft position sensor then as well. They are frequently victims of such an exercise.

 

Already done since trans replacement.

 

Did you replace it? Or merely verify it survived the experience? If you replaced it, what brand did you get? These trucks really don't care for the cheap aftermarket sensors in critical locations.

 

I replaced it with whatever brand I got from Bumper to Bumper hah

 

UPDATE-today it was running really rough and the check engine light started blinking so I pulled over read the codes,
-multiple random cylinder misfire, 1,3&7 I believe
-evap system leak detected
-O2 sensor circuit high voltage bank 1 sensor 1&2

Seems like it got worse today. Gah this thing is frustrating!