A few weeks ago, while I was towing about 1800lbs, My '07 Ranger Sport with a 3.0 Auto, the C.E.L. came on. I had the tow safe mode tune from my SuperChips tuner installed. I pulled over and read the codes with my tuner and it stated "mis-fire #2 cylinder" I cleared the codes and started back down the road. After several times of this happening (on longer grades) I pulled off and re-tuned the truck back to stock. It was ok for a short time. The next morning I re-installed the tow safe tune and the C.E.L. came back on after climbing a grade and stayed on while not pulling anything. I checked the codes and it said "mis-fire multiple cylinders" I put the stock tune back and took it to the dealer and they replaced the heads and plugs and etc... When I asked what could have caused the damage the service writer told me that he has seen this happen at around 90k miles, not 25k. I drove the truck stock for a few days after and it was fine. I re-installed the tow safe tune and started to pull about 1200 lbs and the C.E.L. light came on again. I pulled over, checked the codes "mis-fire #4 cylinder" cleared it, set it back to the stock tune and it's been fine since. Has anyone else experienced this with the same tuner? I run 92 octane always and have never towed more than 2000lbs.

 

I definitely wouldn't blame the tuner. It's a common problem for misfire codes in almost any vehicle especially with how crappy the fuel is now. I just rebuilt the drivers side head on my truck today at work because of the same P0304 and I have no tuner. The carbon buildup from inferior 4 dollar a gallon gas is amazing.

 

do you have any ideas as to what to do to eliminate this propblem? I really don't want to trade this truck in on an f150 while we're paying $4+/gallon. That's why I got this truck in the first place. I went from 14mpg to 20ish mpg