My check engine light came on about a month ago...I checked engine, and it looked happy. I disconnected the battery and re connected it. The light was off and stayed off for about 1000 miles. It came back again yesterday.

What could be the cause of this? The engine still looks and runs happy. I checked

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97' F150 Lariat S/C long bed 4x4 3:55LS 4.6L auto...SuperChip, Air Raid, 40 series Flowmaster cat back.
Colorado Springs, CO

 

DUDE--

Sure sounds like an electrical problem. Hook up a data code reader at the DLC (Diagnostic Link Connector)located under the dash on the drivers side and see what code is shown.

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2000 F-150 XLT, 4x2, 5.4L Supercab, Styleside, Black with silver two-tone, 3.55, class III towing package with heavy duty cooling package, 4 wheel disk ABS, overhead console, sliding rear window, keyless entry, dark graphite interior, in dash CD, Pendaliner bedliner, K&N air filter, rubberized undercoating, cabin filtration system, Bugflector II, 5W-30 Mobil 1, engine build 10/4/99

 

Could it be that lose or leaking gas cap thing again?

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97 F-150 SC Lariat, Styleside, White over Gold, 4.6L (Windsor), Automatic, 3.55 rear end, electronic 4X4, w/ every option of Lariat and ORP packages except the 17" wheels (I even got the OR decals now!) MOD's so far: K&N air box mod, Gibson Super Truck, clear Bugflector II, Leer TSC 600 hard cover, Bridgestone Dueler OWL ATP 265/75 R-16's, TrailMaster Invader N7 shocks, Smittybilt step bars, Ford moulded mud guards, "White-white" head lamps, Cloud Rider Design's SS Grill and bumper opening, Bosch Platinum + 4's, Hayden 30K+ Tranny Cooler,Class III Reece load distributing hitch system, full wiring including trailer battery charging system, Escort Sensor II Brake controller, Superchip

 

It certainly could be...I forgot to mention that..good catch cphilip!



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2000 F-150 XLT, 4x2, 5.4L Supercab, Styleside, Black with silver two-tone, 3.55, class III towing package with heavy duty cooling package, 4 wheel disk ABS, overhead console, sliding rear window, keyless entry, dark graphite interior, in dash CD, Pendaliner bedliner, K&N air filter, rubberized undercoating, cabin filtration system, Bugflector II, 5W-30 Mobil 1, engine build 10/4/99

 

Dustoff,

If your like me it's never the cheap thing that happens to mine so you just get accoustomed to going right to the serious stuff huh?

 

That does seem to be the case!!!

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2000 F-150 XLT, 4x2, 5.4L Supercab, Styleside, Black with silver two-tone, 3.55, class III towing package with heavy duty cooling package, 4 wheel disk ABS, overhead console, sliding rear window, keyless entry, dark graphite interior, in dash CD, Pendaliner bedliner, K&N air filter, rubberized undercoating, cabin filtration system, Bugflector II, 5W-30 Mobil 1, engine build 10/4/99

 

Mine cam on for me a few times and the dealership fixed it under warranty. 1st time was the O2 sensors. 2nd they said nothing was wrong but the light was off when I got it back. 3rd time it eas the mass air flow sensor. With all of these the truck ran fine so It will not be easy to figure out with out a code scanner.

 

Hello all. I have the same problem, but with a 1985 F-150. I gave it a full tune up, rebuilt the carb, checked all vacuum lines, wires ect... and replaced the O2 sensor. The light still stays on. The idle is rough too. Do you think the gas cap thing applies to my F-150? Greg.

 

The "Check Engine" light came on on my wifes 1998 Mercury Mountaineer 2 days ago. I had seen the post about Ford's gas cap and since the Mountaineer is basically a fancy Explorer I thought it could be the problem. Sure enough, my son, who has just started driving, filled the car up for the first time and didn't put the cap on properly. The light stayed on after I put the cap on so I had to disconnect the neg. battery cable. No problem since. I figure just my reading this board saved me from having to visit a dealer.

 

Same happened to me. The light came on and I made an appointment to have it checked. Read somewhere on the site about the gas cap, so I filled up the tank and after six startups the light went out and has stayed off.