Service Engine Soon Light

[keckerb]

I have a '98 S-10 with the 2.2-liter 4-cylinder engine, manual tranny, and 2WD. In the past, the Service Engine Soon light has come on when on long road trips. I checked with the dealer and the guy said it had to do with the gas cap. Sure enough, when I filled up the tank, the light eventually went off.

Recently, the light came on but has not gone off yet. I have filled up the tank, but still the light stays on. For the last few years, I had a locking gas cap on, so I put the original gas cap back on. But still the light stays on. Anyone have any ideas about what may be wrong or how I can find out without paying for a diagnostic?

[Diesel2NR]

did you try adding a fuel cleaner to it? They aren't too expensive. Also, some auto parts stores will hook their diagnostic computer up to your truck and tell you what's wrong for free.

[bgdalovitt]

I had a lot of problems with a service engine light. a couple recommendations.
1. See if yout local auto parts store will read the codes for you. This MIGHT point you in the right direction
2. You need to clear the engine codes - you might have to disconnect the battery for a couple of minutes
2. 90% of Service Engine lights are due to loose electrical connections or vacuum leaks
3. To check for vacuum leaks with the engine runnning, first listen for hissing or you can lightly spray some engine start fluid around the vacuum hoses. (of course be careful for fumes, overspray, & fire) If you spray across a vacuum leak, the engine will increase in spead.
4. Check for loose connection by shaking the wires (other than spark plug) and look for the engine light to come back on.
5. It turned out my service engine light was because of the connector into the computer. I shook the connector back and forth many times and the engine light stopped coming on - that was ~ 3 yrs ago.
6. Another alternative is to take it to a repair shop and pay them to diagnose the problem and you do the repairs. A local shop near me charges $50 for diagnostics
7. good luck!

[keckerb]

I broke down and took it to a local service station that only charged me $32.50 to read the codes. They replaced oxygen sensor #1, and the light is gone. All told, it cost me about $127.00, but I had to get it fixed since I'm selling it. Thanks for your help.