1986 GT Issues

1) The odometer works - The tac works - the speedometer sits at 120 mph (past that). What's the wiring issue? The VSS must be ok since the odometer works. This car (my sons) is driving me nuts!

2) It's running rich - the MPG is about 10 mpg - I'd like to blow it up! I've bought an O2 sensor and an engine coolant temp sensor.

Can anyone help me?

Two separate issues
1) take the Speedo apart and clean the connections
2) check the ecm coolant sensor and mat (iac) sensor for ohms. Cold, they should ohm out almost the same.

The speedo worked fine 5 days ago. What didn't work was the trunk opener so my neighbor did a little work to get the trunk to open and for the trunk light to go on.

I'm just sure (not really lol) this is a ground issue.

The MPG has to be an O2 sensor/coolant sensor/injectors/ etc. etc. (add to the list please).

I'm so frustrated - this is a cool car in great shape but it's driving me crazy. My son loves it but I need to fix this or I'll have to sell it

Welcome to the forum.
This may sound harsh, but you asked what it could be and then argue with the GOOD advice given to you.

Take the advice, check it out, report back.
We are here to help you.

I wasn't arguing......I'm just trying to make sense of things. Sorry if I seemed to be arguing

Yeah, hadn't had coffee yet.
So, what did you find?
And a question....
Did the speedo start acting wonky immediately after your neighbor got the trunk release working?

quote Originally posted by NMW: I've bought an O2 sensor and an engine coolant temp sensor.

Have they been put in?

Th 02 sensor and CTS will go in tomorrow so hopefully that will address the running rich problem.

After that comes the speedo

Let us know what you find. Your findings could help the next guy. Good luck!