I have about 500 miles on a boosted b18c on e85. when i set cruise at 62mph i get this surge it nots real bad but i would like to tune it out. it happens at 3300rpm appr. 292mbar surges to 400 plus on the map sensor. eng temp 172. I thought it was fuel cut. because it never happened pulling up a hill. only on flat land. Everything else is perfect.

 

Do you have a wideband oxygen sensor installed in the vehicle to monitor your lamda?
If not, get one....

 

yes there is a inovate wb. i was actually trying to tune it out. i tryed on the low cam fuel tables no help and i tryed on the ignition table. I am trying to decide if its a car issue or a tune issue. as long as their is a slight load on car like going up a slight hill it will not do it. only when on flat ground. also i am not in closed loop. using Neptune. tuning by self. (novice)

 

"292mbar surges to 400 plus on the map sensor"

i haven't looked in awhile but i know the cruise control system requires vacuum...i wonder if the cruise control system itself is causing a vacuum leak from something faulty in it?

 

I never thought about that but that sure makes sense i will check it out. Thanks much