# Unsteady vacuum on 1.8L engine. (85 Quantum/Corsar) Possible causes?



## IECO (Aug 25, 2014)

Hi. Has anyone done any engine diagnosis using vacuum readings on a 1.8L quantum/passat/corsar engine?
Mine is running smooth overall, but when connecting the vacuum gauge to the manigold, Im seeing the vacuum, which should be steady, is oscillating withing a range, and Im wondering what the problem may be. 
Do you think may be something as simple as the distributor not providing steady ignition or maybe not constant timing across all 4 cylinders? 
I haven't dismantled distributor yet to inspect. 
I'm concerned it may be a motor issue (valves, cylinder lack of compression, etc.) Hopefully not.
This is a carb run engine, but the carb is new (Pierbug/Bocar 2E9), and mixture / carburation, should be good.
I'll try uploading a video of the gauge so it can be better assesed. 
Thanks in advance ! :thumbup:


----------

