94 Buick LeSabre EGR Problem

Hi,

1994 Buick LeSabre 3800 engine 148,000 miles

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

Reply to
Ron Troolin
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Reply to
Bobo

What's a pcm?

Reply to
noyap

Did you clean the carbon out of the ports?

Reply to
BillW

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?

Reply to
Robert Hancock

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

Reply to
Ron Troolin

Reply to
Bobo

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