Check Engine Light on During Acceleration
1992 Jeep Wrangler with 6 cyl in it, I have been getting poor fuel mileage. Im talking like 7 or 8 miles to the gallon but the jeep seems to be running fine. Idles smooth at about 850 rpms at idle and when accelerating there is no hesitation and i have done the following so far.
Changed Plugs, Wires, Cap, Rotor, Fuel pressure regulator, and cleaned the EGR Valve, and also cleaned the Throttle position sensor and have put a new O2 sensor in the exhaust (there is only one and it is before the catalytic converter).
When i am accelerating (it is a 5 speed standard) The check engine light comes on during acceleration once i release the gas and go to the next gear it goes out until my foot touches the gas pedal again. It will do this all the way up to 4th gear. Once i am in 5th gear there is no more check engine light issues whatsoever. I really cant afford to pay someone 75.00 to check the codes and have tried the key on/off thing but it doesn't seem to be working. So i guess my question is... How do i fix this or what could it possibly be?
Also my odometer is off by 10mph. When i am going 35mph i am actually only traveling at 25mph. I have 31in. tires on the jeep no lifts of any kind. Is this cause because of the tire size or could it be something that has to do with my crankshaft positioning sensor? timing? or what? this is all throwing me for a loop here.
Any help is appreciated.