Hi, My 90 TII has a check engine light pop on while driving. It only comes on when Im cruising about 35mph, in 4th gear. The error codes are

17 --- feedback system oxygen sensor output remains 0.55v 10 sec. after F/B
system operation beginning

I think the second code is...
30 --- split air solenoid valve
I suppose it could be "3". Its hard to tell. There are 3 blinks a little shorter than 2 seconds each. No pause between them.

It runs good as long as your giving it gas, even a little bit... But if your just cruising, it sputters sometimes. Then when the CEL comes on, it sputters alot.

Which do you guys think I should check? The Split air solenoid valve, or the O2 sensor? Where is teh split air valve, and what does it look like? Thanks fellas!!

 

I just cleared the codes again and went for a drive. and still getting a 17 and 30. I thought that the 30 code could only come up if I used 5th gear because of the split air valve. I didnt even go into 5th. Anyhow, any ideas?

*UPDATE* I did a little research and just remembered that I dont have a split air valve on my engine. I just put a Jspec engine in, and used the Jspec lower intake manifold. It didnt have a splitair valve. How can I make this code go away? Do I HAVE to have a split air valve to not get a code 30?

 

I suggest getting a new O2 sensor. An original one will be so clogged it's readings will likely be useless to the ECU, hence the code.

The ECU will detect a problem with a solenoid even if it's not active. Follow the error code troubleshooting procedure in the FSM.