Had KD Rotary install Mazda reman. engine last Aug. Have only put 4500 miles on the car, but it's been great EXCEPT for the rough idle which started 1 month ago. At idle, shifter would shake, engine vibration, exhaust would sputter, but upper rpm's seemed fine. Acted like a vacuum leak. Checked TPS, narrow & wide perfect. Pulled BAC connection, idle dropped. When connected, A/C on idle would increase. BAC seemed ok. Checked all vacuum hoses, visually and with spray. Found nothing. Last Saturday, while accelerating normally, the engine "kicked back", actually detonation in 2nd gear. Did it twice that day. Time to call KD. Dropped it off and got a call the next day, BAC was bad. Dave eliminated the BAC, and upped the idle with the throttle. Picked it up last night and drove 1 1/2 hours home....The car ran great!!!!

 

mine is gone on my new project car... we'll see how it runs without anything!

 

Yeah i tested my bac, and even pulled it off to inspect it and it seemed perfectly fine. I might have to block the fugger off. Although my idle issues are MUCH MUCH better now that i've trimmed 800RPM -4% fuel on no throttle, and fixed three vacuum leaks.

 

What rpm does your car idle at now?

 

Any issues with monmentary low idle from power steering, power brakes or a/c loads without the BAC?