2002 Mazda B3000 idles rough and stalls when stopping

2CP-ARCHIVES

MEMBER
2002 MAZDA B3000
6 CYL
2WD
AUTOMATIC
55,000 MILES

2002 Mazda B3000 mileage: 55,000. Recently, the truck has not been running up to par. It started off with the idle speed at low Rpms, {500-600) and would surge up to around 900-1000 and back down. After driving the truck for a few days, the problem became worse and would stall when stopping in traffic. However, the truck ran fine at normal driving speed. {45-65 mph} After a few more times on the road. Since that time, I have replaced the O2 sensor. Also, I have made inspections to the air management and vacuum emission hoses. So far, I cannot locate any leaks. The truck is super clean. I am still having the problem of getting the truck to idle and after the truck reaches normal operating temperature. It will repeat even after resetting the computer. I have scanned the main PCM but no codes what could be wrong?

1 Reply

2CP-ARCHIVES

MEMBER
4,542 POSTS

This is a difficult problem to detect because the computer can not sense a malfunction, the vehicles computer system thinks everything is okay. In reality what is happening is the electrical component inside the MAF sensor becomes contaminated by air impurities. These containment's embed themselves to the electrical component that senses the air flow causing the sensor to be slightly off, but not enough to trigger the MIL (malfunction indicator lamp). Replace the MAF sensor with a new. NOTE: (Mass Air Flow MAF sensor or Air Intake Sensor AIS, depending on manufacturer. It does the same thing only with different names)