vva causing a rough idle?

not unless one of the slave pistons is sticking. but you would notice it more at a higher rpm if it was. if its cold outside and you dont let the motor warm up the oil is still to thick and wont evacuate quick enough making the slave pistons react slow.

 

really nothing to see on the vva's. it sounds like maybe an injector is acting up. is it more like a studder when idling? if so have them do a cutout test and look at the numbers afterwards. i dont think it's an vva thats doing it. they only are supposed to activate under engine load. the reason i say this is when i overhauled my engine i had my injectors checked by an independent shop. it would not idle smoothly afterwards.ran good going down the road, but idled rough. replaced the injectors with new ones and the problem went away. you dont have to replace all injectors just the one that shows up weak. but with that many miles on it it might be a good idea to replace all of them. to freshin it up. it is also a good idea to put in a new injector cup or cups which ever way you go.

 

check fuel pressure. if it is ok then it could be vva's acting up. mine did that every once in a while when i didnt let it warm up to operating temp. but i dont have them anymore,striped them off when i went to a single conversion.

 

then yes i would say its a vva acting up. some times a good cleaning of them works fine. i sent you a pm. let me know if it will help. but make sure thats what it is before you pull the trigger.

 

in the colder weather starting in the 40s mine will start and run fine until i start on the big road. i live 2 miles from where i drop my trailers and the truckstop is just off I70. the 2 miles is thru town so im at slow speed 25 to 35 mph. as i accelerate to speed she will start having a miss and puff out black smoke. after a mile or 2 it will straighten out and run fine. if i plug it in during that kind of weather i have no issues. any ideas on what this could be?