Poor acceleration

Vince · 01-15-2013, 05:05 PM

I have a 2007 GMC Sierra Classic with a 6.6 Duramax and a 6 spd Allison trans. The engine light comes on after driving for 5 to 30 minutes and I lose acceleration power. The engine will only tach up to 1800-2000 RPMs even in neutral. The manual shift selector displays all 6 gears but I cannot downshift with the control buttons. I can get up to speed if on a flat or downhill grade but not on inclines. It hasn't left me sitting but I am worried that it may soon. I replaced the spin off trans filter after receiving that suggestion from an online forum. It didn't make a difference. Any idea what the problem is?

clinebarger · 01-15-2013, 05:10 PM

We need the codes.....If you have a P0700 in the ECM, Check for codes in the TCM.

Vince · 01-15-2013, 05:47 PM

Ok. I dont have a code reader but I believe Auto-Zone will check the codes for free. I'll do that tomorrow. Thanks.

NAFLASH · 01-15-2013, 05:58 PM

When was the fuel filter changed last. How many miles are on the truck? Is the check engine light on?

Sent from my iPhone using AutoGuide.com App

Vince · 01-15-2013, 06:17 PM

The mileage is 205k. The check engine light comes on after driving for 5 to 30 minutes. Thats when the loss of acceleration happens. The fuel filter was changed not long ago. It is currently at 75%.

NAFLASH · 01-15-2013, 07:43 PM

Any mods or all stock engine?

Vince · 01-16-2013, 03:56 AM

Its completely stock.

BGRowan · 01-16-2013, 01:54 PM

Your truck is going into limp mode. A number of things can cause this but without knowing what codes are coming up theres not much we can do. Mine did the same thing when I bought my truck 3 years ago, fuel filter, problem solved. Can't really go by the DIC for filter percentage since it could have been reset at anytime

Vince · 01-16-2013, 04:24 PM

Thanks. I picked up a fuel filter today in case I got some dirty fuel or the filter is just bad for some strange reason. I bought the truck new and have only had fuel filter concernes when I didn't change it after hitting 0%. I had the codes read today and got a P0087 code for fuel pressure too low. It also indicates something about the fuel rail. I didn't make a note of what the exact wording is. Looks like it may need to be repaired by a worthy diesel mechanic if it is within the fuel rail system. Ugh!

clinebarger · 01-16-2013, 05:40 PM

Change the filter first, Clear the code. A plugged fuel filter can cause a P0087.

01-15-2013, 05:05 PM	eBay Motors #1 (permalink)
Vince Join Date: Jan 2013 Posts: 8	Poor acceleration I have a 2007 GMC Sierra Classic with a 6.6 Duramax and a 6 spd Allison trans. The engine light comes on after driving for 5 to 30 minutes and I lose acceleration power. The engine will only tach up to 1800-2000 RPMs even in neutral. The manual shift selector displays all 6 gears but I cannot downshift with the control buttons. I can get up to speed if on a flat or downhill grade but not on inclines. It hasn't left me sitting but I am worried that it may soon. I replaced the spin off trans filter after receiving that suggestion from an online forum. It didn't make a difference. Any idea what the problem is?

01-15-2013, 05:10 PM	eBay Motors #2 (permalink)
clinebarger Senior Member Join Date: Dec 2012 Location: Fort Worth, Texas Posts: 319	We need the codes.....If you have a P0700 in the ECM, Check for codes in the TCM. __________________ 2006 Chevy LT3 CCSB 2500HD LBZ/Allison AirDog 100, Nicktane CAT filter head, Billet bleed screw, Blocked EGR, Bilstein, AAM alum. diff cover, Michelin M/S2. 1985 Chevy C20 Suburban with a '04 5.3L/4L60E K&N intake tube w/ stock box, Built trans, Michelin A/S.

01-15-2013, 05:58 PM	eBay Motors #4 (permalink)
NAFLASH Senior Member Join Date: Jun 2010 Location: Santa Clarita, CA Posts: 387	When was the fuel filter changed last. How many miles are on the truck? Is the check engine light on? Sent from my iPhone using AutoGuide.com App __________________ 2006 Chevy Silverado 2500HD CCSB LBZ 2wd: EFI Live by IdahoRob\|Edge CTS Insight\|Holley HP150\|Nicktane FF adapter\|Diamond Eye 3" downpipe and 4" straight pipe\|S&B Intake\|Transgo Jr.\|EGR Blocked\|PPE Race Valve\|4" CST spindle\|35" Dynapro ATM's\|

01-15-2013, 07:43 PM	eBay Motors #6 (permalink)
NAFLASH Senior Member Join Date: Jun 2010 Location: Santa Clarita, CA Posts: 387	Any mods or all stock engine? __________________ 2006 Chevy Silverado 2500HD CCSB LBZ 2wd: EFI Live by IdahoRob\|Edge CTS Insight\|Holley HP150\|Nicktane FF adapter\|Diamond Eye 3" downpipe and 4" straight pipe\|S&B Intake\|Transgo Jr.\|EGR Blocked\|PPE Race Valve\|4" CST spindle\|35" Dynapro ATM's\|

01-16-2013, 01:54 PM	eBay Motors #8 (permalink)
BGRowan DuramaxForum n00b Join Date: Feb 2010 Posts: 18	Your truck is going into limp mode. A number of things can cause this but without knowing what codes are coming up theres not much we can do. Mine did the same thing when I bought my truck 3 years ago, fuel filter, problem solved. Can't really go by the DIC for filter percentage since it could have been reset at anytime __________________ 2006 Crew Cab LLY LT

01-15-2013, 05:47 PM	eBay Motors #3 (permalink)
Vince Join Date: Jan 2013 Posts: 8	Ok. I dont have a code reader but I believe Auto-Zone will check the codes for free. I'll do that tomorrow. Thanks.

01-15-2013, 06:17 PM	eBay Motors #5 (permalink)
Vince Join Date: Jan 2013 Posts: 8	The mileage is 205k. The check engine light comes on after driving for 5 to 30 minutes. Thats when the loss of acceleration happens. The fuel filter was changed not long ago. It is currently at 75%.

01-16-2013, 03:56 AM	eBay Motors #7 (permalink)
Vince Join Date: Jan 2013 Posts: 8	Its completely stock.

01-16-2013, 04:24 PM	eBay Motors #9 (permalink)
Vince Join Date: Jan 2013 Posts: 8	Thanks. I picked up a fuel filter today in case I got some dirty fuel or the filter is just bad for some strange reason. I bought the truck new and have only had fuel filter concernes when I didn't change it after hitting 0%. I had the codes read today and got a P0087 code for fuel pressure too low. It also indicates something about the fuel rail. I didn't make a note of what the exact wording is. Looks like it may need to be repaired by a worthy diesel mechanic if it is within the fuel rail system. Ugh!

01-16-2013, 05:40 PM	eBay Motors #10 (permalink)
clinebarger Senior Member Join Date: Dec 2012 Location: Fort Worth, Texas Posts: 319	Change the filter first, Clear the code. A plugged fuel filter can cause a P0087. __________________ 2006 Chevy LT3 CCSB 2500HD LBZ/Allison AirDog 100, Nicktane CAT filter head, Billet bleed screw, Blocked EGR, Bilstein, AAM alum. diff cover, Michelin M/S2. 1985 Chevy C20 Suburban with a '04 5.3L/4L60E K&N intake tube w/ stock box, Built trans, Michelin A/S.

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