OK, I never ran into this one before. 1990 F-150 w/ 302 EFI wont pass emissions test because the check engine light came up as inoperative. Also, failed on EGR - No signal. The EGR problem I can dope out, but I don't know where to begin on the check engine light problem (yep, checked the bulb). Any help with this would be greatly appreciated. Thanks.

 

Hey It Could Be An Old Oxygen Sensor. I Have A 300I 6 And I Ran Into The Same Prob.. She Would Run For A While Then The Check Engine Light Would Come On. That Would Be The 1st Thing I Might Check?

 

I realize this is an old post but I am having the same problem with my 99 f150. I took the cluster out replaced the bulb and the light still doesn't work how did you fix your problem finally?

 

I had the same problem with my truck after I put the headers on. I messed around with the EGR valve and was able to get it to work fine for a few years but then it wouldn't go off...so I wired it in conjunction with my ABS light, the check engine light (and ABS light) comes on when the key is turned on and then after the self test on the ABD system both lights go off. That is how I got around smog.

When I disconnect my super charcer (as I always do for smog tests) my truck will pass with less emissions as our 97 Honda Accord.

I heard there was a chip or somethng you can put in the truck if you have headers and this will keep the check engine light 'true'

 

As it turned out, the problem was with the printed circuit board beheind the instrument cluster. There was a small crack in the board where it fed the "check engine" light. I went to the parts store and picked up a kit for repairing rear window defroster elements, and used the conductive liquid to mend the crack in the board. It worked quite well and have not had a problem since. Hope this helps.

 

well I've had it out 3 times now but I'll take it out again and look for a crack thanks a bunch