Rpm seems high ? Reasons?

Check the throttle cable is not sticking, assuming same as the mondial you should see the throttle cable connect to a spring loaded lever. Get some one to press accelerator and when released is it coming all the way off. You can spray some wd 40 on the lever pivot point.
Also check throttle cable not getting caught by the carpet or wrongly routed in the cabin. These are the simple things first

 

Floor mat jammed against pedal?

 

Make sure throttle body is returning to its home position

 

You called it an 83 308GTSi, is it a European model? There is no US 83 308GTSi and it makes a difference. As US 83 would be a 308 GTS QV.

 

Before everyone starts going all over the map here is this something it just started doing or something it's always done or after someone messed with it?

 

So I still have no idea and that makes it hard to be of any help.

Guess I'm not getting an answer.

 

Look for the obvious mechanical stuff first (stickling throttle mechanism or cable, floor mats etc). Check the wear on the roller bearing & slide on the side of the throttle body take the intake hose off & make sure there is nothing obstructing the butterfly or stopping it from closing properly

Then start checking for split or loose hoses & vacuum lines.

If you find something obvious, correct it and if that doesn't resolve it then you might also have a situation where someone has made adjustments with things like the idle mixture on the CIS or the Air idle screw in order to try & fix the thing (when they should have left those things well alone & found the actual cause) Been there, done that!

In which case you then have to figure out what they changed and set it back to where it should, be but go with caution on that.

If its none of that then you probably get into more difficult stuff like the air idle adjustment, the CIS & fuel presures, the warm up regulator, AAV & air injection system - at which point you might need some help.

 

Does the rpm go down after its warmed up? Check to see if the temperature sensor on the expansion tank is still connected.

 

Let's try Brian's question again -- Is it a US version or a euro version?

If it is a US version, another way to ask Jonny Law's question is: Does the yellow "cold running light" in the dash properly illuminate at cold start-up and go off when warmed up? Or does the yellow cold running light never illuminate? Or is the yellow cold-running light always on?

The 1980-83 US 308, having the cold start air valve system, are often modified/mucked with.

 

Start with the mechanical things you can see the movement of, before going on to things like electronics/sensors, etc.

 

This is normal operation for a completely stock US version 1983 308QV. During cold-running (when the yellow cold-running light is on), the cold start air valve allows a lot of extra air to enter the engine raising the idle RPM. Many Owners either disable the cold start air valve system or reduce the amount of air the cold start valve allows to enter the engine to reduce how high the RPM is raised during cold-running. See page 32 of your 260/83 OM which states that the engine RPM will be 2800 +/- 300 RPM at cold start-up.

Are you confirming that during warm-running (when the yellow cold-running light is off) the warm idle RPM is the correct ~1000 RPM?

Not understanding what you mean here -- are you saying it makes driving only during cold-running difficult? Or do you have a problem during warm-running (yellow cold-running light off)?

 

Its best to let these cars warm enough to "move the peg" of the water temp, before driving them, at least I do....

 

Try disconnect the cat O2 sensor. You might have mixture problem. The connector is next to the air box. I was having the same problem for awhile. My mechanic did just that and the problem went away.

 

I had something similar a few years back, was a sticking throttle cable.

Sent from my SM-A505FN using Tapatalk

 

1980-1983 US cars have a vacuum hose routed right past the oil dipstick. When knocked off it raises the idle to about 3000 RPM.

The single most common cause for a stuck idle and the one no one believes is the floor mats. Just remove them to be sure it is not the issue.

 

I never do. It takes too long. My cars get a 10 second or so warm up. Never been a problem.