Just bought 2005 6.0 3wks ago. Ran fine. 2wks ago wife told me when she steps on the brake, it misses a few times. I can hear a hissing noise (like a vaccuum leak), but when stepping on brake it stops, but will miss a few times. Backing down a steep driveway while riding the brake it really misses.

 

Does it miss, or does it have a choppy/loapy Idle? I would pull the connector off the ICP sensor on the pass side valve cover and run it to see if it still does this, if it takes care of the problem then a new ICP sensor will fix your problem

 

Thanks for the reply. It doesn't loap. When backing down a steep driveway and riding the brake, it will miss until I stop/put in drive and go forward. Then it runs fine. When you stop at a light/stop sign, it will miss a couple times then smooth out.

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Mainly does it when brake is applied

 

Test the FICM, there is a test procedure at top of the 6.0 page, could be that. If it does it only when cold it could be stiction, if it does it when hot too it could also be an injector going bad. It would really help to put it on a scanner to read if any codes have been thrown, if it is an injector then it ought to throw a code for that injector, if it throws a code for a bunch of injectors then it is most likely a failing FICM, which can be repaired for alot less then a new one.

 

Ok. I will try the ICP Sensor tomorrow and see if it does anything.