Engine 2002 mustang V6 rough idle in gear at low RPMs


New Member
Mar 25, 2018
Hey everyone!
So I just bought a 2002 mustang v6. 95,000 Miles on the engine, and I’ve already done a lot to fix this thing since I bought it. When I bough the car, I replaced the oil, tranny fluid, coolant, and differential fluid. The car had the classic 3.8 V6 manifold crack, which caused some engine misfires. Swapped out the stock manifolds for BBK shorty headers, new spark plugs, and coil pack, and EGR pipe (original fractured in removal for the headers). Swapping the headers fixed the issues I had, but now the engine shutters at low RPM in gear (around 550 RPM). The car vibrates making the seat and stealing wheel shake, and the shaking gets worse depending how many accessories I have turned on. If the radio, lights, vents and wipers are off, it’s not too bad, if they’re all on, it’s like sitting in a message/vibrator chair. If I put the car into neutral, the vibrating stops (the RPMs go to 750 in N/P) if I hold my foot on the brake and feather the pedal up to 750 while the car is in gear, the vibrating goes away.

MAF sensor is clean
Rest of the car is stock besides the shorty headers.

Please help! How do I fix the vibrating?
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New Member
Apr 6, 2018
I have the same problem on my 03. When I put it into reverse it rumbles down the drive. It stops when I warm up the engine however. Cleaning the MAF didn't do anything for me.