1990 accord engine light/idle/speedometer probs
I have a 1990 Honda Accord LX, manual transmission, 4-cylinder, fuel injection, power everything (steering, locks, windows)...
About halfway to work today I noticed my speedometer dropped to zero as I was still driving. Nothing else seemed wrong so I wasn’t too alarmed thinking it may just be some type of sensor or something and I would eventually have it looked at. I kept an eye on it for a few minutes and noticed that my check engine light came on. I was very alarmed at this because I know it’s obviously not a good thing and also because it’s NEVER come on in my car while driving. I kept going because I was only about 3 miles from work. During the rest of the drive I noticed when the car was stopped or in neutral it was idling terribly low, to the point I assumed it was going to stall if I didn’t keep giving it gas. So I managed the clutch, brake, and gas the rest of the way to work and it seemed fine.
I decided to take it to the shop across the street to have them check the codes to find out what was wrong. When I started it to drive it across the street the check engine light was off and the speedometer was working! Weird I thought. Turned out the shop doesn’t have the right machine/scanner/whatever to check the codes for a 1990 Accord, that’s assuming any codes would even still be there since the light wasn’t on anymore. So there wasn’t much they could do without knowing the problem (and frankly I’d rather not have them guess either). They suggested I change the ignition wires since I had not done that 3 months ago when they did my tune-up because they actually said the wires were fine at the time.
The guy just called me at work to say they did an oil change and replaced the wires and the car was running and idling fine. He drove it around and after about 5 min, the check engine light came on, the speedometer dropped to zero, and the car started idling really low again.
Without knowing the code(s), do any of you know what this could be??? In the back of my mind I was thinking alternator or computer. The alternator is only about 3 years old and all other electrical systems seem fine right now so I guess that’s not it. What about a rusted/corroded wire(s) somewhere? Would something like that cause these 3 problems??
thanks in advance for any help!!!