WILL A BAD MASS AIR FLOW SENSOR MAKE THE COMPUTER RETARD THE ENGINE,OR WHAT MAY BE THE SIMPTOMS OF A BAD AIR FLOW SENSOR- - - HERE'S MY PROBLEM - - -I HAVE A 2002 FREELANDER S WITH 101,000 MILES, AS THE WEATHER GOT COLD THE ENGINE WOULD RUN ROUGH IN THE MORNING WHEN I STARTED IT,IT WOULD START FLASHING THE SERVICE ENGINE SOON LIGHT AND THE MOTOR WOULD LOSE ALL POWER. AFTER RESARTING THE VEHICAL SEVERAL TIMES IT WILL FINALLY CLEAR UP AND ACT LIKE NOTHING WAS EVER WRONG BUT AFTER THE MOTOR GETS COLD AGAIN IT START ALL OVER,WHILE MESSING AROUND WITH IT THE OTHER DAY, I UNPLUGED THE MASS AIR FLOW SENSOR AND IT STARTED RIGHT UP AND HASN'T DONE IT AGAIN, BUT I WOULD LIKE TO KNOW IF THAT COULD BE THE PROBLEM,OR MAYBE IT'S JUST THE MASK OF ANOTHER PROBLEM?

 

Do you have a check engine light on, are you on the originial plug wires, have you changed your O2 sensors, does your exhaust smell and is the tranny having any shifting problems in 3rd or 4th?????
Get back to me.
Mike

 

This sounds very familiar to me. I have replaced all O2 sensors on my 98 p38 and it is still running awful. The dealership said the crank shaft sensor was bad? replacing it is my next step. My rover has 125k on it it has a horrible exaust smell and generally rough running. MAF? I dont know. All spark plugs and wires replaced 5000 miles ago.

 

If the crank sensor was bad it just would not run or stall out when hot and then run when cool.
I say bad MAF.

 

Completely wrong. Its the heads are pitted and they are leaking coolant into the cylinders causing the misfires. Check the spark plugs and if they are coated in coolant or are tinged with pink or orange its the heads. Time for a new engine. Sometimes you can fix the heads but most of the time you cant. They pit and thats all she wrote. Plus its a guaratee that the cylinder walls are probably slipping and letting coolant into the oil. One sure fire to check that is to add dye to the engine and let it run and then drain it. You will see the spots of coolant. What happens is cylinder number four or six will slip and cause some coolant to get in.

 

I just returned from my local dealership and had it plugged back in after installation of my o2 sensors. The dealership is now telling me all 02 sensors are failed and I am getting a misfire code and maf code. Also the service manager said I should reinstall the old 02 sensors in the rear because it is dumping raw fuel into the cats causing the horrible exaust smell. I am confused now! The sensors I bought were Bosch 4 wire. Identical to the ones I removed. No crank sensor code was shown. Check engine light still on and same symptoms as before. Any help would be appreciated. 98 p38 4.0 rover 126,000