Hi all, I have a B5 which mostly runs fine but sometimes from start up it cuts out, ie the engine will run only on acceleration, the moment i lift off it dies, it'll bump start with a jolt or start easily off the key if I'm stationary, after a couple of miles it runs fine again.

Today I cleaned the throttle body and MAF but found a hose from the air intake to the crank breather had gone really soft and the crank breather a sort of S shaped plastic chamber was broken, I replaced the chamber and up rated the hose to something a lot stronger, car hasn't gone bad again yet but I've only gone home in it, 5 miles, could this have been the cause?

The fault when it occurred wasn't random, if I started from cold the car would run fine, a brief stop was ok, but if I let it sit warm for a while then I'd have trouble for a couple of miles, I suspect the heat in the engine bay when the car was stationary would build up as there was no movement and that was the trigger to the problem, now the soft crank vent hose would at this time get even softer and it showed evidence of collapsing on itself so if this hose was to collapse could that cause the engine to cut out when it was off throttle?

 

Well that wasn't the problem, just been out and it's still bad, it does seem to be related to engine bay temperature, once there's an airflow for a while it runs ok but still cuts out momentarily now and then, coil pack perhaps, maybe inlet manifold air leak, no codes, no eml, just concussion from headbutting the windscreen!

Update, I just found the car runs better with the MAF unplugged, could the MAF be causing the issue? anyone? feel free to chip in, anytime?

 

Replaced the MAF, all is good