CEL pops on occasionally

[mhallack]

Got a 1994 XLT (Green Monster) about two weeks ago. And so far all is great on it. Sometimes the CEL will pop on when I first start the truck, maybe once out of every 10 start ups. Most of the time it shuts off after a few seconds, sometimes it stays on the whole drive. I don't notice anything different in performance when the light is on, and I haven't checked the codes yet. Should I even worry about this and would I even get a code if the light doesn't come on?

 

[Roadrunner777]

I'm a "If it ain't broke, don't fix it" kind of guy. But, I would still check into this. There can be problems that do not reflect in performance, but do show up when you work out your gas mileage. And, after you fill this thing up a few times, you are going to get interested in mileage, I think.

 

[MrShorty]

Should I even worry about this and would I even get a code if the light doesn't come on?

Well, I'm not sure if I would enter a "panic" mode, but I'd at least pull the code (the computer has a memory and should remember what fault it was seeing). Where it seems to be intermittent, it might be hard to track down the first time you try, but by pulling the code you can see if the code is always the same or if it brings up different codes depending on the day, and it will give you a beginning place to start looking for short circuits or other.

 

[Jason94sport]

My 93 I got just starting doing it too. Was fine for 100 miles or so. Then I was doing 75 on the HW & it popped on. Still drove fine, stayed on for a few mintes then it went off. Did it a few more times. IDK what it is. Maybe a bad O2, dirty IACV, or MAS. The TB is a new BBK one.

 

[Jason94sport]

I'll throw this in here.....

I checked codes & got a 125, Low TPS voltage. Using the sticky for adjusting the TPS I was getting .88. I loosened the screws & was able to twist it enough to get it to .94-5.
I ran the X & got it to normal temp, I then checked the TPS voltage & got .96, right where it's supposed to be. So far the check engine light has not come back on when driving.