2000 GMC Sierra Fuel Guage Problem

wargle · 08-22-2008, 09:34 PM

I have a 2000 GMC Sierra Z71 with 112K on it. The fuel guage goes crazy when the truck is filled up. The guage goes to empty and after driving a few miles may suddenly go to full where ist should be, then all of a sudden back to empty. After about 60 or 70 miles the guage will read normally. Also, this may be a different problem, but I seem to have lost some power. I pull a 28' camper and the truck doesn't seem to handle the camper as well as it did last year. In addition, I have noticed that after the truck sits for a couple of days, it will stumble when starting. I can key-on, key-off and then crank and it starts fine. Does this sound like a fuel level sender problem and possibly a weak fuel pump? Thanks for the help!

PAPA BEAR · 08-23-2008, 06:48 AM

Sounds like you have it nailed down . but also check the fuel filter and tune up related stuff

ukrkoz · 08-23-2008, 06:27 PM

fuel pump negative and sender unit negative are notorious to go oxydized on those trucks, many posts everywhere about that. problem is, folks say you need to remove truck bed to get to them. unless you are a contortionist with very small hands and have periscopic vision, terminals are hidden so well.
run 2 cans of seafoam through 2 tankfuls. it's very strong medicine.

jimbo543 · 08-25-2008, 02:28 AM

check the fuel pressure regulator on left side of intake with a vacum hose hooked to it, unplug hose and start up then look for gas leaking from regulator, for starting problem. for guage problem, bad fuel sender/meter in tank.

wargle · 08-25-2008, 08:12 PM

Thanks for the advice. I'll start with FPR and then try the Sea Foam, before I tackle the tank.

gmctrucks · 09-03-2008, 03:05 AM

I too love Seafoam it's gold in a can especially for Ford truck owners the EGR passage gets clogged up so use it or fix to spend a ton on money if you take it to a shop.

wargle · 09-15-2008, 02:07 PM

Update: I checked my fuel pressure and with KOEO it reads 52#. Haynes says it should be 55-62#. I can cycle the key several times and the reading does not change. With the engine running the pressure is 48#. with the engine running and unplugging the vacuum line from the FPR the pressure reads 58#. Does this more or less confirm a fuel pump problem? We're talking $275 just for the assembly, so I need to be prety sure that's the problem.

08-22-2008, 09:34 PM	#1
wargle Junior Member Join Date: Jun 2008 Posts: 9	2000 GMC Sierra Fuel Guage Problem I have a 2000 GMC Sierra Z71 with 112K on it. The fuel guage goes crazy when the truck is filled up. The guage goes to empty and after driving a few miles may suddenly go to full where ist should be, then all of a sudden back to empty. After about 60 or 70 miles the guage will read normally. Also, this may be a different problem, but I seem to have lost some power. I pull a 28' camper and the truck doesn't seem to handle the camper as well as it did last year. In addition, I have noticed that after the truck sits for a couple of days, it will stumble when starting. I can key-on, key-off and then crank and it starts fine. Does this sound like a fuel level sender problem and possibly a weak fuel pump? Thanks for the help!

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08-23-2008, 06:48 AM	#2
PAPA BEAR Senior Member Join Date: Mar 2008 Location: virginia Posts: 131	Sounds like you have it nailed down . but also check the fuel filter and tune up related stuff

08-23-2008, 06:27 PM	#3
ukrkoz Senior Member Join Date: Feb 2008 Posts: 172	fuel pump negative and sender unit negative are notorious to go oxydized on those trucks, many posts everywhere about that. problem is, folks say you need to remove truck bed to get to them. unless you are a contortionist with very small hands and have periscopic vision, terminals are hidden so well. run 2 cans of seafoam through 2 tankfuls. it's very strong medicine.

08-25-2008, 02:28 AM	#4
jimbo543 Senior Member Join Date: Sep 2007 Location: MN Posts: 205	check the fuel pressure regulator on left side of intake with a vacum hose hooked to it, unplug hose and start up then look for gas leaking from regulator, for starting problem. for guage problem, bad fuel sender/meter in tank.

08-25-2008, 08:12 PM	#5
wargle Junior Member Join Date: Jun 2008 Posts: 9	Thanks for the advice. I'll start with FPR and then try the Sea Foam, before I tackle the tank.

09-03-2008, 03:05 AM	#6
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 4,035	I too love Seafoam it's gold in a can especially for Ford truck owners the EGR passage gets clogged up so use it or fix to spend a ton on money if you take it to a shop.

09-15-2008, 02:07 PM	#7
wargle Junior Member Join Date: Jun 2008 Posts: 9	Update: I checked my fuel pressure and with KOEO it reads 52#. Haynes says it should be 55-62#. I can cycle the key several times and the reading does not change. With the engine running the pressure is 48#. with the engine running and unplugging the vacuum line from the FPR the pressure reads 58#. Does this more or less confirm a fuel pump problem? We're talking $275 just for the assembly, so I need to be prety sure that's the problem.