please help diagnose. I have a 2004 dodge ram 1500 with 4.7L engine. approximately 150k miles. my issue(s) i have are about 20% of the time on starting vehicle is takes longer than usual to start and starts hard but starts and runs fine once running. as far as i can tell no loss of performance. along with that recently my RPM have been fluctuating right after starting. my usual idle is about 650 RPM and upon some starts my engine will rev itself between 700 RPM to 1200 RPM about 3 or 4 times and will stop doing that. still haven't noticed a loss of performance, maybe a slight decline in gas mileage. i checked a few threads thinking maybe partially clogged fuel filter associated with the first issue but many threads strongly believe that is not the case. so with that information can anyone point me in the correct direction? Thank you.

 

It could be a fuel issue or a vacuum leak or spark plugs or idle air control or throttle position sensor if there is a check engine light on go figure out what the codes are that it is throwing other than that idk

 

Thanks, I have already cleaned my throttle body, I don't have any codes coming up as of yet but the issue is still arising. I may look into a way to clean the idle air control next or possibly just replace it.

 

so after cleaning throttle body and the air intake control valve i believe the wandering rpm's have stopped. its been 3 or 4 days since i've noticed they dont wander anymore. although i still cant pinpoint the rough starts as its about 50% of the time now. ive owned the truck for nearly 30,000 miles and not sure when spark plugs were last replaced.. no battery issues to indicate any battery drain from a poor connection. starter sounds fine and engine trying to crank over but eventually always starts, no misfires, engine surges, or bad acceleration, but if i take it easy on the gas im lucky to reach over 14 mpg, which seems low to me, standards are 16 city and 21 highway and most of my driving is coasting at a comfortable 60 mph otherwise city mpg is maybe at 11 or 12 mpg even with upgraded cold air intake system. with no other signs of bad plugs would this be considered enough evidence to assume the plugs need replacing?

 

got wrong information sorry, avg mpg is 12 city and 16 highway but with an upgraded cold air intake, my mpg should be slightly better but yet yielding bare minimum on avg. again 90% of my driving is coasting 60mph