[T2] '76 bay misfires, sometimes stalls: why?

[David Kelly]

Hello,

I must warn you that you are on a slipper and expensive slope if you just start replacing parts. Been there done that. Your fuel pump will probably either work or not. It should not cause intermittent problems. What type of distributor do you have? Is it an 009? Find the numbers on the side of the dizzy and look them up at the website oldvolkshome.com. If it is a 009, you run out of advance before you get to full throttle. Timing curve is critical in old vw engines. Also a distributor with a worn shaft will cause it to run terribly. If you attach a timing light and the tick mark jumps all over the place this could be it. It has been awhile since I have seen it but you will notice something wrong when you hook up the timing light. If you have points, check your dwell. If it is anything other than 50, the engine is not running at its best. You can also try disconnecting one plug wire at a time while it is running to see if each cylinder is contributing roughly equally. If you find one or 2 cylinders that don't make the engine run rougher than the others when disconnected, expect issues. Check the torque on your head stud nuts. If they are loose, your engine may have overheated in the past. Retorque then reset your valves (unless you have hydraulic valves)  Overheating can also be caused by an insufficient advance curve or a badly timed engine. Other than that, buy yourself a vacuum gage from your FLAPS. check your vacuum levels and tell us what they are. The more vacuum, the better on these fuel injected buses. Finding and eliminating all vacuum leaks will make a world of difference. Oh, another great indicator to tell you how well your bus is running is to pull each spark plug and look at it. They should be a dull grey brown not smutty black or white. 

Anyway, I hope some of this helps. 

David Kelly. 

Also when you say missing, do you mean missing or do you hear small popping sounds from your exhaust? That is back firing which is a different animal all together.