Bucking/Hesitation at low RPM
#27
Rotary for life!
Thread Starter
Tune seems to be great, in saying that this issue has happened for many years. Car has been tuned many times since then going from twin turbo to Single turbo. The engine was rebuilt not long ago with all vac lines replaced. I can't imagine it would be a vac leak?
#29
gross polluter
iTrader: (2)
Vacuum leak can be anything, not necessarily something obvious like a manifold gasket. But any air getting into your intake that the tune does not account for or air leak that causes incorrect MAP reading, that's a problem. Things like a stuck IAC valve, cracked vacuum line, etc.
#30
Rotary for life!
Thread Starter
Not sure how you can assess that the tune is great when you have severe bucking for years. Even if the tune was great nobody would really know. Who are your tuners? Are they always starting with what's already on your ECU and just tweaking it? Are they starting with their own base maps?
Vacuum leak can be anything, not necessarily something obvious like a manifold gasket. But any air getting into your intake that the tune does not account for or air leak that causes incorrect MAP reading, that's a problem. Things like a stuck IAC valve, cracked vacuum line, etc.
Vacuum leak can be anything, not necessarily something obvious like a manifold gasket. But any air getting into your intake that the tune does not account for or air leak that causes incorrect MAP reading, that's a problem. Things like a stuck IAC valve, cracked vacuum line, etc.
When I let the car decelerate down, especially in 2nd, the car heavily jerks back and forth and alot of it can be felt through the transmission which made me think its electrical, its even worse when the car is cold. Not to mention I have an auto harness which I just discovered. Even when I let go of the throttle at lowish rpm, you can feel my gear stick jerk < again, thinking its electrical.
Last edited by rexhvn; 09-04-16 at 03:58 AM.
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