I was on our camping trip, loaded up and towing the trailer in 6th gear, was going to pass a guy on a 2 lane stretch, gave a bitta throttle and I has this little sputter thing and the check engine light came on but the engine was running fine. When I stopped I found I had a p2121 code and shortly after CEL went out.

At the time I was running "performance" on my BDTD (which is what I always run when towing) and level 1 (economy) on my X2 with the street economy down load.

I was not lugging the engine at the time, never thrown a code before and I just put the X2 on before the trip. After that I turned the X2 off and haven't had the problem since, do you think the X2 caused this and/or what do you think I should do?

 

25 reads, anyone?

 

No. Its your apps sensor. I had mine warranteed the first time it went out. The second time it turned out to be the ecm and I had to replace the whole thing. If it doesn't do it anymore don't worry about it. Mine though kept doing it consistantly since it began.

 

I had the same issue while towing and of course had my smarty on 3 and it keep on doing and I would loose my trhottle off and on so I took the sensor off and of course on my truck its located under the drivers side batter and I did have the money at the time to fix it (280 bucks!!) so I put it back on and when I programmed my smarty back to 9 I have had no issues now?? Realy weird...

 

Do you mean didn't have the money at the time, so you never changed it and it's been fine since?

What does the APPS sensor do? Would it have something to do with not enough rail pressure (since I was running the X2 on the economy setting at the time)?

This truck's NEVER missed a beat till this one incident, wonder if it had something to do with the X2?

 

It shouldn't have anything to do with the X2. Mine did it either way. Stock or loaded up with smarty. You may have a different symtom though