LT-1 running rich?

[kpickett]

I've got a '94 LT-1 that I think is running a bit rich. I can't get it in to the dealer for a scan for several weeks, so I wanted to check here if there's anything I can check or do about it myself. It's not bogging or smoking, but there is a gassy smell in the exhaust when we cut the throttle after a slalom run. There's also a bit of black scum on the stern of the boat after a few hours.

I've got new plugs, fuel filter, recent oil change, normal early season maintenance. New thermostats last year - both 143 and 160 were changed out. I know the guages don't show the info the ECM gets, but it's running in its normal temp range, reading 160-170 on the guage. It definetly doesn't seem to be running too cool. Idle is fine, holeshot seems fine. But the gassey smell is strong after a run.

Thanks in advance for any words.

Kyle

[Evan Jones]

Check for any vacuum leaks. That can often be the culprit on these highly computerized engines.

[rektek]

thinking you might have a map sensor issue or the vacuum line to the map sensor.
is it multiport or throttle body injection ?

[kpickett]

I believe that it is multiport injection, but I could be wrong. Where would I find the map sensor?