Join Date: Mar 2011
Location: Phoenix Arizona
iTrader: 0 reviews
I recently did a new exhaust system head's all the way back to tips. The first week after getting my exhaust I noticed a drastic decrease in MPG. Turns out the new Header's had a gasket that was bad at the collector. I replaced it, noticed a small increase in MPG. Replaced plugs, wires, O2 sensors, and gave the ECU a refresher tune and let the car idle for awhile to relearn its internal settings. This brought my MPG back to 200 to the tank, not where I was before the exhaust, so I seafoamed the block, and did a super hot oil change (not a good idea now) replaced the oil filter and added high mileage oil. I'm at 215-230 per tank still not as high as it was before the exhaust but I'm replacing my thermostat today to hopefully bring the operating temperature of the block down.
Side note... K&N air filters (the red ones) should be recharged every 10-15k miles. If you recharge it to much you could lose the charge on the filter thus hurting fuel mileage. You may want to just replace yours and read the manual that comes with it. Also a CAI only helps fuel mileage if it is actually bringing in cold air. If the filter does not have the housing that blocks the motor heat out it isn't worth it. Another option is to custom pipe the air filter into the bumper away from the motor.
Did you check for a vacuum leak?
How's your EGR looking?
Is your check engine light on? If so what code's are you throwing?
Done so far:
windstar, port and polish lower, UDP, aluminum Drive shaft, 3.73lsd, and some other goodies.
Looking for a 4.2 next and maybe some spray.