Usfbeta

99 4 runner v6 5 speed auto with 197,000 miles is has rough idle, stalls out when idle drops to 500 rpm, sluggish during acceleration tut only threw a 0B106 code tonight with no other codes registering. Funny thing is that all fuses were tested, maf and tps have been cleaned, plugs and wires changed, air filter and fuel filter have been changed and still having problem. This just started about three months ago and getting worse now. My engine light is working.

A family friend of ours is a 30 plus year ASE master mechanic/ trainer looked at my truck tonight and he is stumped. He has a very sophisticated code reader that he brought home from work and strange thing was when he tested the car it threw only the code mentioned above which is showing as an airbag sensor. What was strange when he isolated the o2 sensors, the machine read 0.00 on both o2 sensors (which has never seen before) then when he looked at the short term fuel trim it also read 0.00 which would be normal when not picking up any o2 sensor readings. The diag did show a long term fuel trim reading of Negative 20.31 indicating an engine running extremely rich. I know the normal level is between 0 and positive 1. So he wanted to see if anyone had ever seen this diag reading before to see If this is some type of oddball issue anyone has run onto before before replacing the sensors.

He is going to be checking the o2 sensors tomorrow to make sure they are getting 12 volts and he will also be checking the wiring harness to trace the wires to see if any are damaged and that the sensors are sending and receiving signals as they should be. Short of this does anyone know of a problem like this? I have read many of the "rough idle and stalling " forums and we have done most if not all of the cleaning and sensor checks that posters have suggested.

Any thoughts or direction would be greatly appreciated.

Nick
Firefighter/Paramedic
Pasco County Fire Rescue