1992 F150 4,9L 6 cylinder. 225,000 miles

Just preplaced spark plugs, spark plug wire set, distibutor cap and rotor, all Motorcraft parts. Started right up, noticeably more smoother, after driving less than a minute check engine light comes on. Keeps doing it. Don't get it, truck runs better now but light won't go off. Any ideas?

Thanks in advance.

 

disconnect battery for 5 minutes and see if reseting the computer helps out.

while the battery is disconnected look around and make sure nothing is knocked off around where you worked.

 

w/o reading the codes its kind of hard to tell what is wrong. spark plug wires in the right places? did you bump off any vaccum hoses?

 

similar problem now started with bac o2 and went down hill everytime i replace i get a new problem down the line. Now i drive my 92 2wd 4.9 6 and it throws the light on after i go down the road 1-5 mins goes off if i turn the truck off, then comes back after 1-5 mins. Tried to pull the code and the ting cuts the light out on me and i get nothing form it other then pass. I was able to previously pull an o2 code so i know how to get it.

 

my 93 f-150's light has been on/off for 2 yrs. I dive down the road it come on. then a couple min later and it off. Never tried to pull codes because lights never on when i get rdy to pull them. The truck runs great no prob so i just dont worry about it untill one day if it does die i will have to look into it.

 

The light does not have to be on when you pull the codes.
If you do not know how to pull the codes go to this URL:
http://fordfuelinjection.com/?p=13

 

oh my bad i was under the impression that obd-1 had to have the light on to pull codes and the #2 could be pulled at anytime. I guess ill start pulling them, hell maybe there will be a code for NMH (need more horse power) =install supercharger LOL thankyou again for the info

 

I found my problem after pulling the codes and some help in the right direction from subford, well IF you don't want to pull the codes check you vac system and check your egr my 92 inline 6 did the same deal with a few more miles on it thoughover 250000. I manualy pushed the egr with a screwdriver while the motor was running. you hear a difference then it should be working, if the vac is good and your contol side (solonoid valves) of the vac is good. warm your motor up if the egr test works. Turn it off locate the Vac canister (that coffee, or soup can looking thing on the passenger's side over the wheel. dissconnect the hoses and secure them in place not to get moved. Start the motor, and check the pressure one should be dead and one will have vac. IF all is well remove the bolts from the can mount and inspect that can. Mine was rusted out and gave me 311 Thermactor air system inoperative (right side) and 332 EGR valve opening not detected. Also i think there was another one like can't control idle or something. Its a dealer part so call ford for it, about 50 bucks, or find one that is not rusty in the junk yard. Would not be a bad idea to seal that baby from the begining with something thicker than just paint. I was too cheep yet to buy a new one i just fiberglassed (cloth and resin) mine and coated it with spray undercoat and away i go. Also after you find it and "fix" it dissconnect your bat for 10 min or more to be sure that code is gone.