Some specs first: 250ci IL6 4-door completely stock. I was driving the other day to Santa Cruz (woo) and back which is quite a number of miles. By the time I had gotten back, the Maverick can no longer hold a steady idle. Every time I let off the gas, it immediately wants to just die. I have to depress the gas in order to keep it running. When it's running, it goes and sounds relatively normal. When the engine is cold and the choke is activated, it's also normal. Only after a minute of running it from a cold-start does it actually die... I've not an idea about carburetors, but I tried adjusting some of the screws in different directions and combination; however, no avail. Any idea on what this could possibly be? I understand I don't have a proper mixture or else the engine would be running normally correct?
If it has just happened i would say bad gas, put some of that HEAT fluid in the tank to get rid of the water in the gas. I notice it in my car when i run a bad batch of 87 octain, my car likes the 93 for some reason.
Well, this has happened with more than one fuel station. I have replaced the fuel filter. The compression (as far as I know, I could be wrong) doesn't look like it calls for 93 but I'll try some of that HEAT fluid as well as 93.
eh... i wouldnt try 93 with a 6 cylinder car, let alone a stock 302. Vacumm leak or a leaking carb could be possible.
Is there any sort of way of testing a leaky Carb? I could attempt to spray some starter-fluid on the lines to check for the vacuum leak. I wouldn't try the 93 octane either so I guess that idea is out...
Use water(in a spray bottle) to find vacuum leaks...Starting fluid will tell you if you need plug wires in a spectacular fashion.
I may be wrong but i dont think a stuck egr valve would cause the car to die, my car had a stuck egr valve and it would just idle real loud like it had a cam.
a stuck open egr valve should stall out a car. i suspect your idle speed screw has vibrated loose and is now too low to idle. a vaccume leak is also a good possibility.