alisterh 26 Report post Posted August 5, 2015 (edited) I have recently picked up an E30 with the m20b20 motor with a manual box. I have a problem with the car bucking when its at low RPM it is very bad when cold and almost completely gone when warm. It happens when I take off from a stop, when i engine brake and when I go back on the throttle after coasting. I have replaced the distributor cap, rotor, spark plugs. I have checked the CPS, TPS, Coil, and blue temp plug, all seem to be fine. The car seems to be running rich based off the spark plugs. The car seems to pull fine once you get through the bucking. If anyone has any ideas please let me know. Edited August 5, 2015 by alisterh Quote Share this post Link to post Share on other sites
alisterh 26 Report post Posted August 10, 2015 Nothing worse than googling a problem and not seeing an answer so... Turns out it was the AFM, seems like someone thought they new better and adjusted the AFM, the spring tension was so far out that the flap wasn't even closing on its own. I have since adjusted it just based on the feel of the flap compared to another AFM I have (A PFL one) and it is running perfectly now. I still want to get an untampered one, so if anyone has one for a facelift m20b20 AFM let me know. Part number 0 280 202 083 Quote Share this post Link to post Share on other sites
