95 4Runner running bad after head gasket.

[Slowerthanyou]

Just finished doing the head gasket on my 3vze thank god. Anyways the truck has no power in between 1500 and 2500 RPM. I know the 3vze is a slow engine but it's a huge struggle to get it up to 30 mph. It has new plugs and also installed headers. Currently changing the fuel filter that has never been changed. I have read online the O2 sensor could be the problem. It also burned through 1/4 tank of gas in 20 miles. The timing is set at 10 degrees before top dead center. I'm going to try new wires and distributer after the O2 sensor. Anyone have a idea what the problem could be besides what I have listed? 4Runner has 150000 miles.

 

[penbergm]

Did it run fine before the head gasket change? Are you sure both cams are set properly with the crank when the timing belt was off? Have you done a compression test to see if all cylinders are ok?
What was the original issue that made you change the head gaskets?