rlong

Need help i have a 27' baja 502 EFI change the plugs runs fine 5000 rpm about 63mph drop down to 4000 rpm run a little while will only come back to about 4500rpm and 55 slow out of the hole plugs look gas fowled. Anyone had this trouble maybe a sensor i can not find anyone around who has a machine to put it on to check it out.

Jerry B

I would check the diaphram in the vst. I have had both go bad and caused the engines to run very rich. There should not be any gas in the vacume line from the tank to the intake manifold. If there is chances are the diaphram has a hole. I think this failure puts most of the raw gas into #7 cylinder. If all of your plugs are gas fouling this may not be the problem but it does happen allot.
You can do a search on vst and get much more info.

Good luck.

rlong

Thanks but all the plugs are fowled i will be changing the map sensor tomorrow i was told that could be the problem