Mechanics

OXYGEN SENSORS

1997 Ford Aerostar

Engine Performance problem
1997 Ford Aerostar 6 cyl All Wheel Drive Automatic 115000 miles

Hi
The problem started a week ago, the van was running fine, then all of a sudden it started to idle rough, when in gear it is much worse, actually more like a really bad surging plus rough idle acts like it might even stall, when accelerating its terrible! Feels like the thing is running on 3 of the six cylinders, the check engine light came on a few days later, had the code read, and states bad Oxygen Sensors, my question is, could these be causing all of these symptoms, or am I looking at an even larger problem, I don't want to change the Sensors if they won't solve the problem.
Avatar
Volts
September 26, 2010.




Good that you ask. DON'T change your sensors. They are the tattle tells for whats really going on in you engine and are more than likely warning of annother problem. First take your vehicle back and have the scan done again and tell me if they are running RICH or LEAN. Then we can go from here. Larry

Tiny
Larry6354
Sep 27, 2010.
Hi Larry
Ok will do, however I can tell you this much, I do not see black smoke, which would usually indicate a rich mixture, will let you know as soon as I find this information out.

Thanks!

Mark

Tiny
Volts
Sep 28, 2010.
Hi Larry
I have an update for you on the Oxygen sensor issue, I would not be able to tell you if it was Rich or Lean, without having an emissions test done. I have since decided to change out the spark plugs, and figured this would also be a good clue if it was running Rich or Lean, if Rich I should see signs of carbon fouling on the plugs, if not then more than likely it would be Lean if anything. Well I started to take out the plugs and so far in examining them all look used as expected but normal, except for the #1 Spark Plug, in taking it to the auto parts store and having the parts guy look at that one in particular and another of the normal used plugs, he said, after sniffing it and examining it that he thought it was oil fouled. I don't know if this gives you any more of an idea as to what might be going on, given the symptoms its showing, but thought it might help.

Thanks!

Mark

Tiny
Volts
Oct 3, 2010.
I woulden't concern myself so much w/that particular plug. If they didn't look carbon fouled than we gotta assume that you running lean. Get a can of starting fluid. (Aerosol) (Ether) and spray it arround the top of your motor (AS SOON AS YA COME DOWN FROM HIGH IDLE). IF your motor
is drawing air from anyplace it shouldent be you will notice the idle jumping as soon as ya hit the spot. Don't do this on a really hot motor as it gets risky for a fire.

Tiny
Larry6354
Oct 4, 2010.
Hi Larry

Well, I know you stated not to be very concerned with the fouled plug, but I had already taken out the plugs and had news ones to put back in. I hate to be the one to burst your bubble, but after replacing the plugs including the #1 Fouled Plug, the van ran as smooth as could be, took it out for a fair drive, no more surging, engine miss etc. Runs as smooth as can be! I must say I was amazed how one fouled plug can make an engine run so bad! Thanks for all your help and advice!

Mark
AD

Tiny
Volts
Oct 5, 2010.

AD