318i running rough

[e30jones]

Ok, I'm in desperate need of some help

Yesterday, I started up my 84 318i and it is running very rough at idle. I was reading a post in the archives that said something about a pulse sensor being bad, and causing a very rough idle but I'm not sure where this is or if the m10 even has one. Any help locating it would be greatly appreciated (if it even exists)

Any other ideas what could make it run rough at idle --almost seems to be backfiring...

Temp sensor?...

Right now I'm outta ideas......

TIA

[///M Powered]

spark plugs? lol never hurts to check :P

[e30jones]

Nope....replaced them yesterday, I wish it were that easy :(

[KenC]

Are the RPMs steady? Or is it jumping up and down?

[e30jones]

rpms are steady, engine is bouncing and exhaust sounds like a thump every time a piston fires like thump thump thump thump...etc. When I hooked up my timing light to check the timing light goes apeshit flashing very quickly below 2 grand and after 2 grand flashes like it should and engine seems to run fine???

[Bill 84 318i]

Rpms are steady but engine is bouncing? That doesn't make much sense.

Almost sounds like a vacuum leak or something. Start simple and check your vacuum lines.