Hi, I try to figure out if my 355 needs throttle body balancing, so my question is: how 'lumpy' is the 355 idle? Should the engine idle smooth like silk or is normal to have a little bit "lumpy" because of camshafts timing ? I don't have so much experience of different 355 & you people here know a lot. I surched but find nothing on lumpy idle. Thanks for that, V.
A 355 in a very good state of tune idles very smooth. While it is true that throttle body balancing can cause a rough idle, spark plugs and spark plug wires are more often to blame. Compression and bad headers are also common causes.
Mine is also quite stable at idle. Apart when the air-conditioning compressor engage, or when one of the two electric fane engage. During a smale amount of time, the rev decrease (only a bit) and then get compensated by the ECU. I can ear it, by the way. I hope this will help you. Christophe. PS: I own a 97's F355 (Motronic 5.2)
