Vapor lock?

[70spider]

The car runs great for 15 to 20 miles then develops a stumble at low idle. When I come to a stop it has a miss, it doesn't stall but acts as it will if I don't give it more throttle. I have to give it more throttle when I take off in 1st. It also stumbles on acceleration but smooths out with more rpms. When I go into a store and come back out to start it, it doesn't catch fire as quickly as when it is cold. I recently re-jetted the carb but the problem was there before but not as pronounced. Did I lean the carb to much or is it vapor lock?

[lglade]

Is your fuel tank properly venting such that air can come in and replace the volume of fuel that's been used?

[70spider]

Is your fuel tank properly venting such that air can come in and replace the volume of fuel that's been used?

How do you check?

[RRoller123]

Vented cap in that year car I think. The FI uses a sealed system, where tank makeup air only comes in through the charcoal canister. If the tank is low, try driving with the cap off and see if it does it. Full tank may spill all over the place, pretty dangerous..... I think AR has pictures of both type caps on their web site.

[lglade]

You could loosely attach the fuel cap to let air in/out and see if the stalling happens again. Also, if the vent is in the cap, you may be able to just study the cap to figure out if it's plugged or not.

[70spider]

My cap is non-vented, however your test

You could loosely attach the fuel cap to let air in/out and see if the stalling happens again

is still valid. When I got the car I had the fuel tank lined and the place that did it tried not to clog up the vent lines but the diameter of the holes were greatly reduced. So today, if it doesn't rain I am going for a drive and when it begins to stumble I'll loosen the fuel cap and see if that solves the problem. Thanks for the help.

[124JOE]

also check your plug wires pull one end off at a time and inspect,replace it before you pull the next,do the cap end then the pulg end

[70spider]

Well, no luck. I loosened the gas cap with no effect. I then checked the carb itself and noticed two of the nuts not so tight so I tightened them, still no luck. As for the wires I also thought it might be the issue so I replaced them with new ones, no luck. The odd thing is this issue isn't consistent, at times it goes away for a while after I run through the gears and some times it persistent? Could this be my blow by problem? #2 cylinder is down on compression. Oh well, I have to live with it until I get the cash to finish my 1608.
Thanks for all the great suggestions.