I have an 05 with 200,000 miles. Got some bad fuel awhile ago, but after cleaning tank, lines, filters, truck started running right again.

yesterday, it started to sound like it had a miss in neutral or park, but cleared up as soon as it went into gear.
Changed fuel filter, Still looked good.
Drained filter, added seafoam to filter, started and run for half hour
Repeated process second time,
Still sounds like missing when in neutral.

When missing, there is no fluctuation in rpm
Fuel pressure is 8 psi at idle and 6 at WOT
When in nuetral and rev engine too 2000 rpm, rpm's will not drop immediately. They fluctuate between 2000 and 2200 for aprox 10 sec before dropping back down.

Does not miss or act abnornal towing 20,000 lbs and climbing hills.

Any insight would be very much appreciated

Thanks
Jim

 

Same thing happenend to my 06', missing at idle, and would not idle down properly. Your injectors are leaking, I had to replace all six. Make sure though with them leaking you don't rev it up to much in park or neutral it could run away on you.