Hi,
Engine misfires/chuggles at part throttle and light load (about 60 mph). Has good acceleration/performance otherwise. P1406 History code. Scan tool shows EGR Actual % swings wildly when the chuggle happens but the EGR Desired is steady.. Engine runs great when EGR is unplugged. Tried a new EGR valve and it didn't fix the problem. Intake manifold vacuum is high and steady when EGR is disconnected. I could use some suggestions!!!!
Thanks,
Ron
What's a pcm?
Did you clean the carbon out of the ports?
Could be something like a bad EGR pintle position sensor (part of the valve). Is the actual value staying pretty close to the desired when it's running OK?
Hi,
Thanks for the suggestions guys! I hope it's not the PCM but not hard to replace if it is. I didn't see any carbon in the ports so that isn't the problem. Robert, the actual value stays close to desired until the engine starts to run rough then it swings wildly. I replaced the EGR with a new GM valve and it did the same thing. Again, the engine runs really good with the EGR valve unplugged.
Thanks.
Ron
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