JXNRoush

New to the forums, thanks in advance for any help. I have a 05 Roush, 1.9 VMP TVS, long tubes/no cats, hot rod cams, 60 lb injectors and Kenne Bell BAP. The 1.9 blower is recent as well as the 60 lb injectors and BAP to support the increased power (513 rwhp). Car was dyno tuned.

Here's the issue; after picking the car up I noticed a hesitation when shifting on the way home. The RPMs drop and the car bucks before the power comes back up within seconds. The idle is also off a bit. No CEL. Scanned the car and got P2198, signal biased/stuck rich. Spent a few weeks trouble shooting between work trips. I found that if I remove the BAP, the car runs great (taking it easy since no BAP). Runs absolutely perfect, no codes..smooth as silk. Ran the car for 30 miles of easy driving without an issue.

Thought I may have had a bad BAP, so I bought a new Kenne Bell BAP as I just wanted the car running (should have tested the first unit). Installed per instructions. Started car and idle was again off. Before getting out of the driveway the hesitation/bucking was back. No CEL. Took BAP back out, runs perfect again. BAP is good. I am at a loss. Tuner has no idea as well. Any suggestions?

jwog666

the BAP is not your problem, it can only add fuel pressure under boost, start by diagnosing the p2198 code, removing the BAP is most likely hiding the real cause as you are now running lean without it