vacuum problem?

[mule13]

so last couple days ive noticed the truck seems to miss at cruising speeds .

on the way to work this morning i tried turning off the heater and lo and behold

the idle/engine rpm stopped the rough running. my question is would the lower

vacuum becuase of the heater taking vacuum cause this somehow?

I'm not sure how vacuum affects this honestly theres no vacuum advance on

the distrubitor its all electronic so i'm not sure, how it would make the engine miss during normal

driving conditions.

 

Thanks John

[jimoshel]

It affects the air, fuel ratio.

[mule13]

Jim,

thanks for the reply, the normal operation of the heater shouldnt effect the operation of the motor should it?

i havent heard any vacuum leaks, but i will chck again tomorrow when i have time. anything else i should look for you can think of?

 

Thanks John

[jimoshel]

Normal heater operation won't affect it. Sometimes finding a vacuum leak can be a bear. One method is to remove all vacuum accessories as close to the source (intake manifold) as possible. Then hook them back up, one at a time. Helps narrow it down a little. Be sure and block off any open lines when doing this.