4.0 rough idle question

[SMTGREG]

P0301 = #1 misfire... P0305 = #5 misfire... p0300 = multiple cyl misfire or unable to define misfire due to cam position failure. During a cold start spray some carb cleaner around the intake gaskets if engine speed changes you have a vacume leak, intake gaskets will leak more when engine is cold. Next could be injector flow or spray pattern problems (dirty injectors). Least likely would be carbon buildup on the back of the intake valves. The carbon soaks up the fuel on cold starts causing engine to idle rough

 

[Roger Jolly]

I have sprayed carb cleaner all around the intake mating surfaces with no change in idle speed. I guess the next stop is injectors.
Thanks for your help.

 

[fireguy12117]

i kind of read this quickly, so sorry if i missed a point or two, but-

have you done continuity checks on the wiring back to the computer? i had a poor idle problem for the longest time. 2 IAC's, multiple times to the shop, and it ended up being a broken wire inside the wiring harness. turns out the whole harness was ultimatly bad with broken corroded connections however the truck would run, just never quite right, and never idled right. never threw a code either, but anyhow, checking the wiring between computer and sensor would ensure that what you are seeing as good components are seen as good by the PCM.

 

[Roger Jolly]

I have been thinking about doing just that. I need to take the time to do it. Thanks.

 

[Roger Jolly]

Found out what it is. #1 cylinder has 40 pounds compression.