So my new-to-me 1992 4runner with the 22re was getting around 25-26 mpg highway mileage and I was ecstatic. Then the headgasket blew, but when I ripped it apart, the timing chain guide had failed and so I would've needed to rip into it anyways, so that was ok.

But now that it's back together, the mileage has gone down to around 20 mpg on the highway. Which is pretty dissapointing.

I put in a new timing chain, new spark plug wires and distributor and adjusted the valves while I was in there - though the valves were pretty good - I think I just tweaked one intake and one exhaust.. I'd done the plugs shortly before it blew - unfortunately I can't remember what the mileage was after I did the plugs but before the new HG. Other than that, nothing should have changed. The timing is set to 5 before tdc now - not sure what it might have been before, but the marks I made on the dist. before the job line up perfectly.

Anybody have any ideas? I know I was getting better than average mileage out of it before, especially considering it's on 31s - but I'd really like to get back some of these losses.

 

Did you have to mill the head? If so, that could retard the cam timing a bit, though I wouldn't expect to lose +10% mileage.

But if the head gasket went, and blew coolant into the catalytic converter, I could see that plugging up and reducing your mileage.