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Truck info: 2007 GMC 2500HD Classic LBZ, Stock with 287,000 miles. Had been running great with no noticeable issues.

So with all of this crazy covid-19 stuffy going on my company decided to let us take our company vehicles homes....which is nice. Anyways, my truck sat for about 2 weeks without driving it and when I did go to drive it the CIL came on and the truck was in limp mode, limited to 2K rpms. It drives fine, shifts fine, idles fine, but no power and limited to 2K rpms. Hooked a scanner up to it and it gave me the dreaded P0087 code....so I'm looking for some help.

It had been about 9K miles since my last fuel filter change, which I actually change rather faithfully every 10K miles...so I changed it figuring it was a dirty fuel filter. I dumped the fuel into a clear jar as usual and WTF...there was definitely water in the fuel. Not just a few drops but what I would considered too much. And no, Water In Fuel never came up on the dash. I put a new WIF sensor on last year but obviously it was faulty.

I plan on draining the tank (will probably put some in clear jars to see how much water is in it), dropping it and cleaning it. I am also planning on checking the straw for ubstructions and all low pressure lines for leaks. But let's be real, what's the odds that the high pressure side is OK, ie. CP3...Injectors? I know the FPRV can also cause the same problem son if nothing is found on the low pressure side I will pull that too. What should I be looking for with that?

Any other suggestions?

I know if I come out of this alive, not having to replace the whole high pressure side that I'm gonna be installing an airdog 2 4g, bypassing the factory fuel filter and get EFI live asap....well I probably will do that anyways. Thanks for any advice and/or suggestions in advance.
 

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Perhaps there wasn't enough water in the filter for the float to trigger? Also, you're gonna drain the whole tank for some water in the filter?

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Discussion Starter #3
Well, there is only about 1/4 tank left. I cleared the code but within 10 miles the CIL came back on and it never came out of limp mode. Just try to limit all possibilities from the tank to the cp3.
 

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I would bottle test it next to rule out the fprv. If it's hung open it would likely fill the bottle pretty quick. If you don't see anything at first maybe drive it a little bit and check again. If it is the fprv and it immediately codes on start up then I'd say it's hung open.

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Discussion Starter #5
UPDATE: dropped the fuel tank and there was a decent amount of crude in the bottom of the fuel pick module. Not to mention inside the "fittings" on the top where the fuel supply and return lines connect there was a quite a bit of rust. So I replaced the fuel pickup module and problem solved. Definitely a big sigh of relief.
 
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