My wifes 2.2 96 OBW all the sudden dipped to the 23 MPG range and CEL came on. I was doing some cheap expirements first before I had the light checked. Good ol SeaFoam in thrugh the PCV. It filled the hose up twice with nothing going into the intake and then dawn broke on granite rock. Why isn't the SeaFoam going thrugh like the times before? Unscrewed the PCV and lo and behold, all gummed up. Sort of odd as I change them regularly but hey. I dumped a few drops of Sea Foam in the PCV and shook it up and dumped it out. Did that a few times just to get by. Completed the SeaFoam treatment. CEL went off just like that. I will change PCV and monitor MPG to see if it goes back up to the 26-27 around town MPG.

 

After all of that intro, would a blocked PCV effect MPG?

 

Thanks,

Greg

It might. Less scavenging of the blowby gases from the crankcase due to a blocked PCV would be the cause. Normally, the engine recycles the fuel it didn't burn through the PCV. So it could be possible that the injection system would feed more fuel to compensate.

Mine did. Between that and the issue with my intake system that Ive yet to discover (my iac valve isnt sucking air at all like its supposed to when at idle sometimes it just creates a vacuum but from what know about iacs thats not how its supposed to work)

Anyways my no good PCV valve was giving me something close to the teens when I replaced it (it got bad enough to where I just didnt wanna know how mad my mileage was) after I replaced it I'm back up to about 25mpg freeway, which is almost what I was getting beforehand so Im not entirely worried.