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Post by littlemitz329 on Aug 18, 2020 21:31:54 GMT -6
First post; I've got a 97 autobahn which is having some idling issues. The engines shakes back and forth quite a bit on idle, the whole exhaust system shakes, u can feel it inside the car. The exhaust also smells different there is very strong fumes coming out of it. It is misfiring as the tach jumps up and down a little but even when it isn't moving a lot the shaking is still there, some of the interior lights occasionally flicker. I also noticed a bit of power loss. I think it's an electrical issue; I have replaced spark plugs, spark plug wires, and 2/4 ignition coils but I swapped them around and it didn't help at all. Before I go and spend more money, does anyone know what this problem is? thx. Could it be plugged exhaust?
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Post by Marc on Aug 19, 2020 7:58:14 GMT -6
A possibility: crankshaft position sensors. Have it scanned to be certain.
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RCA1186
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Rob
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Post by RCA1186 on Aug 19, 2020 8:07:55 GMT -6
Does the car even out when you apply the gas? Like 1500-2000 rpm? Could be a number of things, vacuum leak, fueling issue
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tigger
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Post by tigger on Aug 19, 2020 16:53:20 GMT -6
Pull the plug wire off of each plug and listen for idle change (one at a time, listen then replace). The one, or ones, that don't change the idle aren't firing...
And as Rob said, could be any of a number of things. But you can isolate the issue by swapping plugs, packs, wires, and injectors...
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Post by littlemitz329 on Aug 19, 2020 22:01:57 GMT -6
Does the car even out when you apply the gas? Like 1500-2000 rpm? Could be a number of things, vacuum leak, fueling issue It actually does, it becomes smooth when i give a little throttle. I will scan the codes tomorrow and see what the computer says about it. |
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Post by littlemitz329 on Aug 19, 2020 22:06:24 GMT -6
A possibility: crankshaft position sensors. Have it scanned to be certain. There are multiple? Is replacing those sensors an easy task by any means? |
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RCA1186
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Rob
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Post by RCA1186 on Aug 20, 2020 6:43:46 GMT -6
I'd check your vacuum hoses and the backfire valve on the serpentine belt side of the intake, listen for hissing/sucking/whistling noises
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Post by Marc on Aug 20, 2020 8:00:45 GMT -6
A possibility: crankshaft position sensors. Have it scanned to be certain. There are multiple? Is replacing those sensors an easy task by any means? No. You need a Tech 2 scan tool to calibrate the sensors after you put them in. There are 2 of them. And I think that the oil filter & the oil filter mount have to be removed to get to those sensors. |
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Post by littlemitz329 on Aug 30, 2020 3:41:20 GMT -6
I'd check your vacuum hoses and the backfire valve on the serpentine belt side of the intake, listen for hissing/sucking/whistling noises Sorry for the late reply. You were exactly right, it was the backfire valve. The O rings are shot, half of it was missing. Where can I find these o rings nowadays? I saw a previous thread which mentioned an ACDELCO part number but I could not find it. |
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RCA1186
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Rob
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Post by RCA1186 on Sept 1, 2020 7:09:26 GMT -6
This thread (that you may have seen) shows the part number of the valve itself in the posts. I'm not sure what the number for the o-ring would be unfortunately. You may be able to bring it into a part's store and compare but that might be a little tough. A lot of people have siliconed that nuisance shut with good results.
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