Severe lag with gas pedal | Ford Explorer Forums - Serious Explorations

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Severe lag with gas pedal


April 7, 2008
Reaction score
City, State
Louisburg, KS
Year, Model & Trim Level
94 XLT 4x4
Ok after we changed O2 sensors the Exp is running worse. You can push the gas pedal all the way in, and release....then the engine revs and comes down. Its like we have a massive lag or relay in the compression of the gas pedal. Almost sputters, and when your driving it will be fine, then you feel yourself slowing down. The pedal will be to the floor and you keep slowing down, then it bucks or hops. Its worse when you first drive it for the day, on the way home from work it runs almost normal.

Does this sound like fuel pump? We changed fuel filter in Feb. Sitting at idol it doesn't miss, but the minute you hit the gas it begins sputtering.

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if you replaced the 02 sensors, you need to reset the computer if you haven't done so all ready. if you haven't, just disconnect the negative battery terminal for about ten minutes, letting all residual charges drain from the truck's sytem. this will allow the computer to "forget" the air/fuel ratios it's learned, and it'll re-learn them.

i do this before every trip over 100 miles, and also once every two weeks. makes sure i get the best mileage available.

let us know if you've done this all ready, and we'll move on to other possibilites

Yes we did unplug battery cables and also cleared codes with the code reader. Tonight it drove perfectly fine home, which makes no sense unless the truck just likes going South instead of North! 3 Hr earlier I had to take a back road and get off highway as it was running so bad. As you push the gas you realise its on the floor and your slowing down.

Could a vacuum leak cause this, only asking because my cruise surges so I don't use it. Always assumed it was a vacuum leak, maybe its connected.

Just tossing ideas out, we are clueless.

Thanks again for all suggestions

...I've never heard of a vacuum leak being that drastic...I would disconnect the cruise vacuum lines and plug them up first...It sounds like the diaphragm in your cruise servo is shot...This will help for starters...I do not think this is all your problems but reset your computer again after disconnecting and plugging those lines...

...The next time you have a problem, have your codes read for stored codes...You may even have some now but I'm thinking disconnecting your vacuum leaking servo will help to have fewer codes...:dunno:

Got Codes

How do I have more codes now that I replaced both O2 sensors!?!?!? I don't get it.

Codes as of this morning. Cleared them with reader & unplugged Neg. Cable.

327 o & c
172 176 181 186 189 c after all codes

Oil & filters changed every 3 months.
Plugs, wires, Air filter & Fuel filter changed this year.
EGR Valve & Sensor 11-07

MAF, fuel pump or regulator is what we are leaning toward.

This is just crazy, we paid $70 bucks to have codes professionally ran a couple months ago because engine light comes on. Has for years, last year same thing, they tell us nothing is wrong!!! We have to pay, and nothing is fixed. So bought a reader from O'riellys and we get codes upon codes. Sometimes living in rural areas the mechanic selection is rather poor.

...First, did you disconnect the cruise vacuum line and cap it???

...I see all your codes are lean codes...I think this could be a number of things...Fuel pump, FPR, IAC, TPS, MAF, Electrical problem maybe...:dunno:

...This might be of some help...;)

MAF fixed everything!

Well we unplugged the MAF sensor and sure enough the truck died, then started right up and ran like I forgot it could. You push the gas pedal down, and it actually revs up!! We swore it was the fuel filter or fuel pump. Half the guys on our block had bets going it was that. Nope...

Changed MAF and the truck purrs!! Check engine light still came on but the only code we pull now is 327 o & c .

Codes before MAF change:
172 176 181 186 189 327

YEA....... Thanks everyone