1995 GMC Yukon • 150,000 miles

I have a 1995 GMC Yukon that has a rough idle and when coming from a stop, it will spit and sputter for a second before taking off. The heater is also not working. I was told that these problems could be related and be a vacuum issue. I have replaced the EGR valve, MAP sensor and EGR solenoid and checked the vacuum diagram under the hood and all lines seem to be in good order. The heater fuse in the cab is also fine. Where would you suggest I go from here?
December 23, 2011.

Heater possibilities is low coolant, bad thermostat, clogged heater core or blend door issue.
The miss could be from a plug or coil failure but a compression test is in order before throwing any parts at it.


Dec 23, 2011.
Check the idle air control valve, EGR valve and TPS sensor for the rough idle-

Heater: Power the blower motor direct from the battery and see if it'll turn on

Dec 23, 2011.