I have '99 Outback, 2.5L, manual transmission with 174,000 miles on it. I've had the car for about a year and a half. I've been living with and trying to solve this problem for a couple months: The engine stumbles on acceleration unless I'm very gentle on the throttle. It's worse when the engine is warm. Here's what I've done so far:
Read codes for EGR malfunction, misfire in cylinders 2 & 3, and knock sensor circuit malfunction. I cleaned the EGR tube and valve and verified that the valve moves and the diaphram holds vacuum. That took care of the EGR code. The car ran much better, but still not great. The misfire and knock sensor codes still came up after about 20 miles of driving.
For the second round, I replaced the fuel filter and spark plugs. No noticable improvement. I later found a maintenance record that showed the plugs had only 30,000 miles on them (NGK Iridium). I replaced them with a similar plug made by Denso.
The last thing I did was replace the knock sensor. This seems to have made an improvement, but I think it's still not as good as it should be. The CEL stayed off for a couple hundred miles but came on again when I didn't downshift soon enough and lugged the engine a little. Codes were again missfire in cylinders 2&3 and knock sensor fault.
Most of my driving is on the highway, and there it runs fine. The problems occur at under about 2200 rpm. Any suggestions?
Thanks!
Dave
Read codes for EGR malfunction, misfire in cylinders 2 & 3, and knock sensor circuit malfunction. I cleaned the EGR tube and valve and verified that the valve moves and the diaphram holds vacuum. That took care of the EGR code. The car ran much better, but still not great. The misfire and knock sensor codes still came up after about 20 miles of driving.
For the second round, I replaced the fuel filter and spark plugs. No noticable improvement. I later found a maintenance record that showed the plugs had only 30,000 miles on them (NGK Iridium). I replaced them with a similar plug made by Denso.
The last thing I did was replace the knock sensor. This seems to have made an improvement, but I think it's still not as good as it should be. The CEL stayed off for a couple hundred miles but came on again when I didn't downshift soon enough and lugged the engine a little. Codes were again missfire in cylinders 2&3 and knock sensor fault.
Most of my driving is on the highway, and there it runs fine. The problems occur at under about 2200 rpm. Any suggestions?
Thanks!
Dave