Like all of us I am sick of the gas prices. I'm in a hurry so this info might seem kind of mixed up or lacking at the moment. I have always kind of wondered about the fuel mixture, but I do not have any type of stand alone fuel manangement software/hardware. What could i do? I have flown airplanes that are carbed and fuel injected, but both are able to lean the fuel mixture mechanically. Hmmm, well today my engine on my 1997 Ford Ranger started to run rough at idle. I thought bad egr valve and the poor iac motor was trying like crazy to keep a good idle. Bank one was lean according to the code I pulled and the dpfe sensor is not working(big surprise), so the egr is not working anyways then. Usually I use a quarter tank of gas driving from Findlay, OH to Lima, OH. This time I only used a 1/8th of a tank! Ah ha, a vacuum leak causing my engine to run lean.(could be a bad maf sensor or an actually bad upstream O2 sensor) Figured I sucked the intake gasket in , but it was actually a broke vacuum line and that would explain the erratic idle. I do not have an egt guage/meter. How much hotter do you think my egt temps are? The block and head are cast iron(2.3 liter engine). What im thinking of doing is running a one way check valve that only opens when i'm on the highway when pulling a certain vacuum. That way in town under normal stop and go conditions the one way check valve stays closed do to low vacuum pressure and idles normal. Can i use a laser/info red thermomter to check my egt temps? I have one of those. What do you guys think? I realize the check engine light will never go out because of the lean condition on the highway, but I don't care about that. This little engine is almost like a diesel compared to reliability and strength. I think the pistons would be the weak link (burn a hole through one or more). I doubled my mileage on the highway. I heard no ping or engine detonation while on the highway. It ran great and I had a bit more power in 5th gear, just wouldnt idle for crap at red light and thats where the check valve comes in. Hmm, gonna need forged pistons I think. Let me know what you think and I'll fix some of the spelling later. Thanks