[bennettbrowder3]

Ive got a Max effort 416 engine with all the bells and whistles, big cam, heads, 2inch kooks headers, ATi dampener, BMR engine mounts, Monster triple disc clutch, MM mild Catch can, GPI plug wires, New O2 sensors, NGK plugs, ported/spacered Hiram, Lt4 injectors and HP pump, NW TB, and OTR air intake. Built and tuned by Pray Performance. Runs on pump E85. It has ran great for 2000 miles, but has recently developed a dipping idle when cold, and is getting worse. It dips so low that it almost dies, but mostly clears up after its warm. On part throttle accel it waves back and forth, like Waaah waaah, waaah. Even with constant pedal, it feels like your leting off the gas and back on. WOT is not affected. I have checked Hiram,TB torques, sprayed Carb cleaner all over the Hiram and Vac line connections multiple times, but cannot find a Vac leak. Recorded a log yesterday and had P0300 random missfire, TB % at idle bounced between 17-22, and Longterm fuel trim was -9 and -10. Sounds and acts like a Vac leak.....but i cant find it?? Anyone??

[18.2SS.1LE]

If it was a vacuum leak, your fuel trims should've been positive. Does your oil smell heavily like fuel?

[bennettbrowder3]

Im not sure about the oil, as I have just changed it and only drove 30-40 miles since.

[grampa_ss]

I'd start with sending datalogs to your tuner.

[bennettbrowder3]

Currently doing that also, just takes a while.

[bennettbrowder3]

Originally Posted by 18.2SS.1LE

If it was a vacuum leak, your fuel trims should've been positive. Does your oil smell heavily like fuel?

I got the oil sample back from Blackstone and its definitely not heavy on fuel.

Fuel% <0.5 Should be <2.0 So I have less than average fuel in the oil.