What would cause the car to run progressively richer?

I don;t have a good suggestion on the running rich, but if it smells strongly of gas it could be damaging the catalytic converter if you still have one. They are expensive to replace, so avoiding damage is good. Even if they aren't a requirement where you are, and for an '85 I doubt they are anywhere but maybe California, they do cut down on odor.

 

Try new oxygen sensors...although I did not have a problem of re-starting, that cured a similar problem on my t.

 

I don't know, but I think it is manual. Mine has Two not One oxygen sensors.

 

An ignition problem can cause that condition - since the ignition system is set up as two separate 4 cylinder systems (each bank has separate coil, distributor, Digiplex electronics), it is possible to have one ignition system cut out and then the engine will run with only 4 cylinders firing - but it will be way down on power, and the non-firing 4 cylinders are just pumping fuel through the cylinders and out the exhaust...

One common cause of one bank's ignition cutting out is a failing flywheel sensor - there are 3 sensors on a QV, one specific to each bank, and a common one for the tachometer signal. The sensors can become heat sensitive where they work well when cold, then start cutting out when engine heat builds up.

Gordon

 

After: completely rebuilt the fuel distributor, warm up regulator and replaced the fuel injectors as a few were leaking;
Send it back to the mechanic. Let him stand behind his work.

 

Did the mechanic rebuild the fuel distributor or did he send it out. I have been told there are only two shops in the US that do this service. One is in mobile alabama. I think your fuel dist. is still dumping too much fuel into the cylinder. I had a similar thing with my 86' 3.2.

 

Time for the Italian tune-up, i.e, ROAD TRIP. Works for me and my t.

 

Run up I 65 to Nashville, then I 40 to Memphis, then US 78 back home.

 

Since the car ran better after replacing the cracked cap, that might be a clue. Perhaps a plug wire is not seated correctly in the cap (new reproduction caps sometimes have the wire hole not being deep enough for the brass pin to pierce properly the wire, you have to carefully drill the hole a bit deeeper), or the carbon button/spring is stuck.

 

It's not really "mechanical", more electrical via the fuel pressure from the pump and the fuel quantity is air mass regulated (via, I admit, a mechanical link).

 

Absolutely yes; rich for cold start, lean for partial load conditions and WOT enriching (the 2 air hoses from the plenum to the WUR, plus engine heat). It's all handled by WUR and uses excess fuel pressure and quantity to control the FD. Additionally, the AAV and cold start injector helps cold start plus overcoming higher internal resistance with a cold engine.

 

Besides ignition, you could have a failing thermo-time switch controlling the cold start injector, which would leak fuel. Disconnect it and see if it changes anything.