My 84 380se starts fine when cold and idles good, but as soon as you put your foot into the accelerator it either stalls or hesitates and backfires and wont idle up. If you try and accelerate it slow it is Ok, but not driveable. Only after 10 minutes or so when the engine is warm does it seems to be OK and is driveable. It almost seems as it pops out the intake and the fuel economy gauge pins right out. What could be the problem?

Not sure. Are these cars fuel injected? Have you checked the air and fuel filters?

yup...but not sure exacly what system....bosch?

I see. I think is is Bosch.....

__________________
2004 Toyota Sequoia Limited 4wd
1991 Lincoln Town Car Executive
1991 Cadillac Sedan DeVille
1988 Mercedes 300SEL
1972 Chevrolet Caprice Kingswood Estate 9-passenger wagon
1973 Pontiac Grand Ville
(Prior MB's: 1974 240D, 1985 380SE, 1984 190D, 1993 400SEL)

runs same with air filter removed....if it was fuel filter it would run crappy all the time

True. Did you re-install the air filter? It is not recommended to run it without this, because a backfire could result in an engine fire. You may already know that, but just thought I would mention it to be safe. In addition, some cars will not run properly without the air filters installed.