So Weird Problem.....

[tylerdude49]

first off i have searched the forums and have found no thread like this lol. So ihav a 1993 mark viii with 200,000 km on it with all scheduled maintenance done and a recent tune up ( plugs wires filter oil etc...) The other day i was stopped at a traf light and the car started lurching so i popped it into neutral, the car was still revving up to about 1800 rpm then would drop then rev again then drop then rev the drop etc... As it was revving up the chek eng light would come on then turn off as it dropped down, as it was dropping dow the overdrive off light would come on. The car kept doing this until the light went green and i was able to pull it over. I turned it off. I waited a few mins and started it again. It still was running rough but without the chek light and the revving, So i turned it off again and waited some more. I started it again and it ran beautifully?? I was headed to the airport to pik my fiancee up so i had to continue on. A few km later the chek eng light came on and the car wouldnt shift into over drive and the push buttom on the shifter wouldnt even turn the light on the dash on. I left the car. Wen i returnd i had a code reader and did a engn on test and a key on test. The car held no codes??? wtf. The problem hasnt happnd since and the car has been running fine. Any ideas? stumped!

 

[mespock]

I believe a Gen I codes will clear once the key is turned off... not 100% on this but I think I remember this from many million post before.

 

[tylerdude49]

ok so problem happend again, I pulled over and put the code reader on it right away and if just flashed at me as fast as the engine light was flashing and wouldnt do anything else. I turned the car off and tryd to do just a key on code read but still the same issue. You can hear a bunch of clicking and noises, so i followed my ears. It was the fuel pump relay clickn on and off ( this would explain the irratic idle). What would cause the relay to be kicking on and off? any ideas please!

 

[Markviiiedrea]

Sounds like a TPS senssor, what's the code?

 

[Gambler]

ok so problem happend again, I pulled over and put the code reader on it right away and if just flashed at me as fast as the engine light was flashing and wouldnt do anything else. I turned the car off and tryd to do just a key on code read but still the same issue. You can hear a bunch of clicking and noises, so i followed my ears. It was the fuel pump relay clickn on and off ( this would explain the irratic idle). What would cause the relay to be kicking on and off? any ideas please!

that relay is a high speed fuel pump relay if ur talkin bout the one under the hood and i had problems with a bad computer clicking that on and off and my idle was fine so it must be somthing else. and with a good scanner your car WILL give u any stored history codes no matter if it flashed and went off or stayed on. u just need a decent scanner like an old snap on brick or somthing, and u go into history codes, or pending codes. since these are older cars i dont remember if it has those but you need to do the KOER test and it will bring up all codes, my 93 brought up history codes. the car need to see 2 complete run throughs of the certin system with no falt to clear the code from the pcm. hope that helps somewhat haha