I have an 89 3.9L V6 with 169K mi that has been running rough for a while. Initially, the engine would hiccup while driving and got progressively worse until power would drop significantly for a short period while driving or stall when at idle. I looked at the error codes, which included one that indicated an apparent problem with the oxygen sensor. Since I didn't want to replace a $60 component without knowing for sure that it was bad I took the truck into the Dodge dealer and paid $150 for them to troubleshoot. The reported that the oxygen sensor and the driver side fuel injector were bad. I replaced both and it ran well for about two days, then started the same behavior again, only worse. It will start-up and run fine for a few miles, then the power drops are worse and for longer periods. The engine light now comes on and stays on. I collected the error codes, as follows:

26 Injector circuits have high resistance
33 A/C clutch cutout relay circuit
52 Oxygen sensor stuck at rich position

None of these codes should cause the engine light to come on (except 52 and only on California models, which this isn't). Can the other fuel injector be bad? or possibly other sensors (map). Is it possible that the oxygen sensor wasn't bad to begin with and that it is another sensor causing the 52 code? I was thinking about running the truck until symptoms appear, then looking at the fuel injector flow, if the flow is intermittent on the side I didn't replace, is it the injector? or maybe the computer? If isolated to a single injector I would suspect a sensor, the fuel pump, or fuel filter since they should affect fuel flow to both injectors? I'm just trying to save myself a few $ bypassing troubleshooting at the dealer.

Thanks for any help!

 

Sounds to me like your fuel injector is sticking or just not working properly. Or wire to the injectors. Check ever wire. The o2 code says its rich. Which meens the injector is puting to much gas in it. the other code says the ac relay circut is faulty. so maybe the wires are shorting out together there or may be a differnt problem. You may also have a vacuum leak or something like that. check all hoses. reset the computer by taking off the battery connectors for 60sec than put them back on and run the truck see if they come back on. most places like autozone or checkers or pepboys will check the engine light for free or a low $5 fee.