after installing battery wires backwards for a split second. there was a spark... yes I know ugh.
Is there a fuse that does something with idle control? I believe the round red plastic part at the back of the IP does this?

Nothing will make the car rough... it may idle slower at idle, but not rough... if you took out the ovp fuse I suppose idle enhancement could be lost. Not sure where it is on a 126

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

indeed it was ovp fuse. Forgot about that thing, sits kind of above windshield wiper motor. Idle was so low that it was starving for fuel, which made it run "not smooth" to say the least!!