325is bucking and cutting out

[billythekid]

I've been having issues with bucking and stalling. Started about a year ago as a minor issue would just cut out at 4k if I was really romping on it. It's progressed to intermittent bucking, flashing cel but most times doesn't throw a code. Only code I got it to throw recently was 1222, before that it was a 1215 I believe. Things I've checked/replaced: cap and rotor, intake elbow, cleaned carbon track in afm and throughout cleaned the contact points trap door etc. Sprayed out the tps(switch doesn't engage/click at wot), cleaned icv, cleaned ground strap mount point from power steering pump to frame, run injector cleaner through it, shit that removes water from gas, overall car runs better but issue remains. One thing I think isn't normal is when I undo the hose for the fuel regulator and plug the manifold side with my finger it doesn't run any different, is this a sign the regulator is bad?(also should mention the cut out at higher roms and most/ all throttle started after changing water pump/timing belt)

[tomstin]

A few thoughts, since this started after the timing belt. Is the crank position sensor adjusted correctly and does the cable look good? After cleaning the Throttle Position Switch (TPS) does it now work at idle and wide open throttle (check with multi meter)? Local auto parts stores should be able to lend / rent a fuel pressure tester which is the only way to verify the fuel pressure. The AFMs are all showing their age, the only way to verify is having them rebuilt or swapping in a know good unit. Cleaning is worth a try but without the experience with proper testing these units, your guessing.

Sorry, no easy answers. Good luck getting this sorted.

[billythekid]

Thanks for the reply, I'll do what ever I really can without a multimeter. Unless I can find one that works well for a small sum of money

[Gregs///M]

AFM failure usually results in sudden and brief power loss, usually around the mid range of the RPM range. It can also cause poor idle and lack of power. This sounds like a failing AFM to me. If your CPS was failed, the car will never start. If your TPS was not adjusted, it would have poor idle only. The fact that is runs ok and cuts out around 4k is classic AFM failure.