I have this 90, with the 300 and a 5-speed. i have done a full tuneup on it and it still pops at idle and gets terrible milage. Like 160 to a tank. On the big tank thats about 8 mpg! Anyway if you think there is something i could do or something I've missed let me know. It has a cap on it right now and also has a big k&n filter and a flowmaster muff. and no cat. so i can't seem to find what's getting in the way.

Thansk

 

What do you mean by "pops"? Is it a back fire, or a miss, etc.? Was it doing this before the tune up? What was included in the tune up (plugs, wires, cap, rotor, coil, etc.)?

 

Well, like a miss but it did this before and after the tune-up. Which was just wires,plug's and a cap and rotor. I've heard of just cleaning any varnish off the throttlebody may help and when changing the plugs they looked more white that i would like so maybe it's also a small intake leak.