01-04-2016, 11:20 AM
I'm having some trouble determining the problem with my 97 Tracker. It's got about 190 000kms on it and has been running good up until lately. It has always been a little hard on fuel due to lift, bumpers, winch, bigger tires etc.
A few months back, I noticed that it was pinging quite badly under load on the highway. I tried mid grade fuel, with no difference. About the same time, I got a P0400 EGR code. After some research, I ended up cleaning out the EGR Tube as well as the port in the intake. I just removed the air intake tube, opened the butterfly and used a long screwdriver to clear the blockage. This solved the problem of the P0400 code and the pinging was gone.
Fast forward a couple months, and I notice that the idle is starting to become erratic, first slightly, then over time it becomes jumpy and the motor shuddesr, almost stalls, revs dipping from down to almost stalling up to about 1200 rpms. Initially, when I was driving, the problem was not noticable, only at idle. Eventually the idle became more erratic and I started noticing hesitations and bucking at part throttle. If I go more than 1/2 throttle when I'm driving, the problem doesn't present. Only under light load or idle.
I've replaced the O2 sensor, checked the TPS resistance for idle switch and a full sweep to look for dead spots. It checked out just fine. I pulled the Idle control valve just to eliminate it. It seemed fine, no major buildup. Also I didn't really think this was the problem since the hesitation and missing occur even above idle. I have new plugs (old plugs were BLACK!), checked the cap and rotor and cleaned up the contacts.
I manually cycled the EGR valve by pushing on the diaphragm just to make sure it wasn't stuck, it definitely moves freely.
Most of the time, there are no codes and no CEL present. One time I did get a P0121 TP Circuit Performance Problem but I reset it and it hasn't showed up since. I feel the TPS sweep and idle switch test rule this out.
I did unplug the MAF to trigger limp mode and the idle smooths out and hesitation/miss disappears.
I'm not sure what I should do from here.
Any insight or suggestions would be greatly appreciated.
Thanks,
Mike
A few months back, I noticed that it was pinging quite badly under load on the highway. I tried mid grade fuel, with no difference. About the same time, I got a P0400 EGR code. After some research, I ended up cleaning out the EGR Tube as well as the port in the intake. I just removed the air intake tube, opened the butterfly and used a long screwdriver to clear the blockage. This solved the problem of the P0400 code and the pinging was gone.
Fast forward a couple months, and I notice that the idle is starting to become erratic, first slightly, then over time it becomes jumpy and the motor shuddesr, almost stalls, revs dipping from down to almost stalling up to about 1200 rpms. Initially, when I was driving, the problem was not noticable, only at idle. Eventually the idle became more erratic and I started noticing hesitations and bucking at part throttle. If I go more than 1/2 throttle when I'm driving, the problem doesn't present. Only under light load or idle.
I've replaced the O2 sensor, checked the TPS resistance for idle switch and a full sweep to look for dead spots. It checked out just fine. I pulled the Idle control valve just to eliminate it. It seemed fine, no major buildup. Also I didn't really think this was the problem since the hesitation and missing occur even above idle. I have new plugs (old plugs were BLACK!), checked the cap and rotor and cleaned up the contacts.
I manually cycled the EGR valve by pushing on the diaphragm just to make sure it wasn't stuck, it definitely moves freely.
Most of the time, there are no codes and no CEL present. One time I did get a P0121 TP Circuit Performance Problem but I reset it and it hasn't showed up since. I feel the TPS sweep and idle switch test rule this out.
I did unplug the MAF to trigger limp mode and the idle smooths out and hesitation/miss disappears.
I'm not sure what I should do from here.
Any insight or suggestions would be greatly appreciated.
Thanks,
Mike