mh1988

i am asking this for somebody elses truck
the prob he is having is his idle has been sticking off and on for about 2 weeks. It will just stay at around 1250 it still revs up fine and drive fine. i did the on off on off thing to pull the codes and the only code that came up is pcu 0500 we stopped by the dodge house to see what the code meant but that code isn't supposed to be on a diesel according to them. that code is only on gasoline eng. and its something like a no speed sensor signal or something. his speedo is working just fine. now what else could be causing the idle stick and why would that code be on there? oh and he just had his 3rd apps module installed in the last year about 4 weeks ago.