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Discussion Starter #1
My car ('08 Impala 9C1 with 3.9) has a surge/miss/hesitation that the dealer says is normal...the car alternating between 3 and 6 cylinders.

Although I doubt this is the cause of my complaint, I wonder if it is possible to have the car run on all 6 cylinders all the time?

Anyone accomplished this? Reuslts? Thanks in advance for responding.
 

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How many miles on the engine and when was the last time the plugs and wires were changed? I would at least try a full tune up first.

If your warranty is up then you might have the PCM retuned to deactivate the DOD software. The only draw back is that it will use a little more fuel running on all cylinders all of the time.
 

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Discussion Starter #4
Thanks for the replies so far...

The car has 92K miles. I installed new OEM spark plugs, along with many different brands of fuel injector cleaner and Seafoam treatment to try and cure my issue.

Maybe I should try plug wires too? They appear to be in good shape, I inspected them each and cleaned them off with WD40 when I changed the plugs.

Sorry to be ignorant, but what is the "PCM", and where/how would I get it reprogrammed? I may give that a shot when my warranty is up.

Thanks again, anyone else care to advise?
 

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PCM is the master engine computer which controls all aspects of engine function. It is what turns on the "Check Engine" lamp when there is a problem. Located under the hood near your air filter box. Run a search for whom to use to reprogram it. Also if you do some add ons such as Cold Air Intake, new exhaust and such you will want all of that done before retuning the PCM.
 

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When does the surge happen? If it is at idle. Yes, it is normal. I did some searching on this subject. It appears that at idle a injector will not fire every so often.

Why? It is a stupid reason to me. Overall fuel savings. My thought is over a life of the car your gonna save maybe one tank of gas.

Another thing. Do not use WD40 on rubber. It breaks it down. If you want to know if your wires are bad. Wet them down with water. You can use a test light for this. Clip on goes to battery ground. You use the probe end and run it over the wires. About a 1/16 of a inch away. If it just sparks. They are bad. Or if you have arching marks.

Have you changed your fuel filter? You use good fuel? I ask that because about 3 weeks ago we had a vehicle come in running like crap. Bad fuel.

So, if your not feeling the surge at idle. Is it when your DOD goes into effect? A little surge is normal.
 
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