check engine light comes on holds no codes

[Jimmy94]

Hey everybody, total noob here so bear with me, I have a 94 w/4.0 that I get intermintent check engine light but when I had it scanned (twice) it does not show any codes, my mechanic says possibly the speed sensor is bad has anyone else had this issue, its all original w/116,00 miles any help or suggestions would be great as I don't want to start throwing money at could be's

 

[Raw16057]

I had a 94 187,000 miles that did the same thing. It was the fuel pump, no sensors there.

 

[Explorin94]

Has this mechanic checked for codes in the memory of the computer? Has the light been on for longer than 30 seconds? If not then it won't store any codes. If it doesn't affect the running of the vehicle I wouldn't worry about it until it goes all the way out. Then you will have an idea of where to start.

 

[Jimmy94]

thanks

Hey guys thanks for your response, finally took it to my mechanic for a diag, they cleaned the MAF sensor and did a high pressure fuel system cleaning, injectors, throttle body etc. runs better than ever w/no more check engine, cost $300.00 but seems to be worth it so far. Hope this can help somebody else.

 

[Jimmy94]

update

two days after MAF cleaning and fuel system cleaning truck ran worse than before when cold, took it back to shop and they figured out that the EGR valve was sticking open on cold start up apparently the OBD 1 system doesn't hold any codes or give any info so its fix what you find first and go from there, anyways 3 days later so far so good and $160.00 broker.

 

[Explorin94]

I put a non-egr intake plenum off a 92 on my 94 Ex. Welded the hole shut in the manifold and ran great after that.