5.0 Gas problem found... how to fix.
03-07-2010, 02:44 AM
#1
Thread Starter
Join Date: Feb 2010
Location: California
Posts: 6
5.0 Gas problem found... how to fix.
I made a thread about a month or two ago about my 5.0, that i love so much, about having gas problems. For example I went from 20 in town down to 13. So long story short I replaced and tried different things to help this problem. Well nothing worked untill I talked to the ford dealership and talked to a "guy". What had happened is that I replaced my stock mufflers and tail pipe to14" flow masters with 2 1/2 inch tail pipe. After i had done that thats when i had my problem. Well, he told me that I changed my back pressure. That changed my o2 sensor readings to my MAF and CPU. So the CPU thinks im running too lean according to my 02's and so im dumping more gas than i should. Question: Is there a place where I can get my o2's and MAF and CPU to run and read on the same level? I was told to go to a performance shop and have them CHIP the computer. The closest one for me would be in Sacramento. Any other ideas? Or am i just going to have to bite the bullet? Thanks for your time.
03-07-2010, 03:05 AM
#2
1st Gear Member
Join Date: Dec 2008
Location: SoCal
Posts: 93
I think your O2 sensor is bad, i cant see why your muffler would cause this problem. Back pressure has nothing to do with making your car run leaner. I would replace your O2 sensor and see if it helps. Could be just a lazy O2 sensor not switching.
Last edited by STROKED_LX; 03-07-2010 at 05:55 PM.
03-07-2010, 08:46 AM
#3
2nd Gear Member
Join Date: Oct 2009
Location: Florida
Posts: 429
Have you pulled codes from the computer? If so, was the O2 faulting? Your car could easily have bad O2 sensors. Does your car reach operating temperature? If not, you could be remaining in 'closed loop', thus in a RICH condition. You do have a drop in MPG, so you are dumping in too much gas.
Changing you mufflers is no big deal for the computer to compensate for. Your problem is somewhere else. Pull codes.
Changing you mufflers is no big deal for the computer to compensate for. Your problem is somewhere else. Pull codes.
Last edited by MustangBradley; 03-07-2010 at 08:48 AM. Reason: A
03-07-2010, 01:00 PM
#4
M.A.D. Motorsports
Join Date: Jul 2006
Location: Indiana
Posts: 8,014
I made a thread about a month or two ago about my 5.0, that i love so much, about having gas problems. For example I went from 20 in town down to 13. So long story short I replaced and tried different things to help this problem. Well nothing worked untill I talked to the ford dealership and talked to a "guy". What had happened is that I replaced my stock mufflers and tail pipe to14" flow masters with 2 1/2 inch tail pipe. After i had done that thats when i had my problem. Well, he told me that I changed my back pressure. That changed my o2 sensor readings to my MAF and CPU. So the CPU thinks im running too lean according to my 02's and so im dumping more gas than i should. Question: Is there a place where I can get my o2's and MAF and CPU to run and read on the same level? I was told to go to a performance shop and have them CHIP the computer. The closest one for me would be in Sacramento. Any other ideas? Or am i just going to have to bite the bullet? Thanks for your time.
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