Check Engine Light/ No Codes

[Guest]

Greetings,
I have a '97 Expedition - 5.4 - XLT. I've been having the same problem now for about a year and it's driving me nuts. On occasion when starting the vehicle the Check Eng light comes on, Idle Drops (sometimes she stalls) and its as though she's starting out in 4th gear (no 1st, 2nd etc). Dumps some major fuel too!
Other times both Check Eng and Theft Light are on at the same time. No codes are present!
To correct the problem I usually have to Lock and Unlock the vehicle using the OEM Security Remote or diconnect the battery for a few hours. I have replaced the key(thinking that would fix it but no luck)....any thoughts??
Thxs!

 

[PaulC]

Does it happen during or after snow or rainfall?

 

[Guest]

Replying - Check Eng Light No Code

Happens at any moment it feels like doing so. At first I thought it was heat related, lol...but it will do it in any weather condition.

Thxs
Carlo

 

[PaulC]

My thought was that the General Electronic Module (GEM), located behind the fusebox under the dash, was becoming wet from a water leak eminating from the windshield base/cowl area.

Not uncommon.