i have noticed under the oil cap in my engine block that there is a beige colour film buildup..any thoughts
also my truck seems to idle a bit lousy periodically...though it never stalls..all plugs are intact..though have not been check as i had them replaced early this year....your help is appreciated

 

Beige color sounds like water in the oil.

 

High humidity and moisture in the crankcase causes the film to condense on cooler surfaces.
Usually not a long term issue unless it's there all the time.
Trucks that are not driven long enough to fully heat from a cold start are more prone to this.
Normally, the crankcase will be under some pressure from ring blow-by.
The crankcase is a closed system that is vented by the vacuum from the intake to remove the vapors and burn them in cylinder combustion.
If there is a inlet leak from the outside, a code may be set because the PCM has monitor capability to detect it.

 

If its just on the cap, then its condensation. basically what bluegrass said, the engine wasnt up to temp long enough to burn it off.

its normal

 

Yep, normal, but clean it off and check the PCV system once in awhile. Blow it out. Short trips, high idle times in the winter mouths add up under the cam covers.

 

1. I agree with the previous posts. The white film under the oil cap may be from the oil not reaching the proper temp, maybee you have a short drive or live in a cold place. I had the same issue when I lived in Wa. state. My short drive time to work combined with the cold wet air= mocha cream under the oil cap. I thought for the longest time it was a leaking head gasket or worse. I just kept an eye on my coolant level.
2. The rough idle may be a vacuum leak, or perhaps your upper manifold(behind the throttle body) may need a good cleaning. I think there are a couple of write ups about this, use the search. I too had a rough idle, so i looked at the upper manifold, and sure enough, some of the passages were gummed and caked with carbon buildup. Particuarly the passages leading to the EGR valve. Those passages were almost completely clogged.
Hope this helps you out, and welcome to the forums.
The more questions you ask, the more you know

 

this makestotal sense i tend to have a habit of getting up real early 5am and taking off without warmup due to not disturbing neighbours..thanks so much to those responses!