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View Full Version : 98 EB Running very RICH and poor MPG... Katmandu 11-17-2002, 11:01 PM It's got 44k miles, 4.0 SOHC, Auto and had the 00M12 ONP recalls done. The filters are all in good shape and there are no other obvious issues. The tailpipe is pitch black and the mileage has been dropping. Ideas on what to check out ?? Jason_25 11-17-2002, 11:03 PM Surely you have a check engine light on then? Or have you in the past? Katmandu 11-17-2002, 11:04 PM Originally posted by Jason_25 Surely you have a check engine light on then? Or have you in the past? Nope. Not since the recall was performed about a year ago. Alec 11-17-2002, 11:41 PM First thing I'd check is the FPR, fuel pressure regulator. If I'm not mistaken, 98+ the fuel regulation system changed, but there's still a part that regulates fuel flow to the motor. If it's not that, could be dirty MAS, multiple leaky injectors (not likely), or bad O2 sensors. Could also be a stuck open thermostat: is the truck always running cold? Bottomlesspit 11-17-2002, 11:55 PM I definitely second for you to check out what Alec said. The mass air meter on my stang did the same thing to me. The tailpipes were filthy black and spewing lots of fumes. The MAS was messed up, telling the computer to send in too much fuel. The computer sent no codes, or check engine light either. It would not hurt to run codes to be sure. How about vac leaks? Have you checked all the vac lines for broken, leaking lines? Getting extra air (uncalibrated by the MAS) into the engine can get you running lean, so the computer will respond with additional fuel. Just some more starting points for you. Good luck...and post findings so all may learn. Ken Katmandu 11-18-2002, 11:05 AM Good tips guys! Only real problem now is my wife has the truck back up home in Ohio. I'm currently serving time in a Federal installation in LA !! I'll translate that! I'm currently serving on Active duty USAF stationed at Maxwell, AFB Montgomery, AL (Lower Alabama)! Hopefully, I'll be able to get back up home by the end of January when I'm eligible to retire! Come to think of it....it does run cool. I'll replace the thermostat. What temperature thermostat should I use ?? I'll clean the MAF as well when I get back up to the Buckeye. BradE. 11-18-2002, 12:13 PM Use a 192/195 temp thermostat. :) |