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Discussion Starter #1 (Edited)
Hello, I know there are other posts about the surging idle issue and I am just wondering if Fuel pressure regulator is probably what is wrong with my truck before i throw parts at my truck.

I recently bought a 2002 GMC sierra with the 6.6 LB7 and the truck surges at idle when its in park or in drive. I have tried the fuel additive Diesel Kleen didnt have much affect on the surge. From visual inspection the fuel lines seem fine.

The truck has a fairly strong diesel fuel smell in the exhaust but does not smoke at all. Also there is a SES code on the motor right now its a MAF sensor out of range code not sure if that would affect the surging idle.

So i am not sure if it is the FPR or perhaps injectors or any other problem.

Any help would be appreciated, Thanks!

** Edit **

Also i am not sure of the mileage on this truck because whoever had it before replaced the dash on the truck judging by the wear i would say 200-300,000 miles

Also this is my first diesel truck so i am kinda new to this
 

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My Quess is the fpr, but i would take the maf sensor out and clean it with only maf cleaner only, and allow it to dry completely before putting it back in.
 

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Mine does the same thing. Don't worry about it til it breaks, then put aftermarket performance parts in its place:drink:rockin
 

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yah mine does it 2, and its very random not like a cycle? what causes that?
 

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Mine doesnt seem very random there is an even time between surges and it doesnt go away.
Same here. Get and ADII and chalk it up to that. When it's still surging, get the valve. That way your ole lady can't get mad at you got dropping the $630 on lift pump:rockin
 

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are you having to prime your filter occasionally or everyday?
 

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I would agree its the FPR.
 

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its the fpr but if your gonna pay 400 for that you might as well get a new cp3 for a little more cash when you buy the cp3 you also get a new fpr so its worth it to me
 

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the same thing was happening to my truck one of the valves were stuck i put 2 quarts of ATF in with the fuel and ran it staight untill i almost emptied the tank, it ended up fixing it worth a try anyway
 

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Mine does the same thing...obvious surge at idle. I use stanadyne performance and that helps a little, but it's still there. If you look at your injector balance rates you can definitely tell as they tend to jump around a lot. You can buy the FPR online for around $175 shipped all day if you look around.
 

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FPR fixed the surging idle

Changed mine this weekend and what a difference it made...idles flat and steady as can be now. It was kind of a pain in the arse, but worth it.
I got the part at a fairly local place here in michigan for 213.?? after tax.
 
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