Just purchased an 02 Dakota sxt 4x4 with a 3.9, only 26,000 miles. The thing is backfiring and missing, mileage is poor, smell raw gas. throwing right bank rich, cyl 1, 3 misfires. The day I bought it the headlights wouldnt turn on, dealer says the forward control module was bad, they replaced it. My vision of the lot attend. blowing high pressure water into another cars engine compartment keeps flashing into my mind. Is it likely that by cleaning the motor this way that the kid ruined the forward control module, and other sensors, and most likely what sensor is causing the backfire and missing. MAP, TPS or even the ECU.
The truck is absolutely showroom condition otherwise. Not as nice as my 2012 Ram/Hemi but way nice for my 17 yo son.
Should i let the dealer fix or just cancel the deal and find something else.

Well here we are, the dealer picked up truck by flat bed, had the truck for two days. Service guy calls and says "The O2 sensor was shorting out". I asked which sensor upstream or down, asked what diagnostics were done etc. The guy has no answers, just says "Its done, in the lot with keys in the visor if you wanna get it tonight(its saturday at 430 pm) or you can wait till Monday. I get my daughter and son and law to ride me to the dealer( about 35 minutes). I get into the truck, starts right up, drive 45 yards, just enough to get on a major 4 lane highway and .... You guessed it. Misfiring, no power and no accelleration. I get off the highway walk back to the dealer and tell the lone salesman, 1 I am very unhappy and 2 the dealer gets one more shot to fix this thing, I made him take notes and told him I wanted both o2's replaced, the MAP sensor replaced the TPS replaced and a complete tuneup with cap, rotor plugs and wires. If that doesnt work then Ill allow the dealership to replace the ECU. Or give me my money back.