This article is from the Chrysler-Plymouth-Dodge FAQ, by Dr. David Zatz with numerous contributions by others.
Switched from Getty and Citgo gas to Mobil, Amoco, and Gulf.
Made a tremendous difference.
EGR valve may be stuck open or rusted off.
Engine idled erratically when warm, sometimes lost power after first
response when accelerator pressed about 1/3-1/4 down. Dealer first
adjusted venting at gas tank, seemed to help the idle. Then cleaned and
sealed the battery connector, solving the problem; was probably bad
battery connection causing system voltage fluctuation, which caused
changes in the controls. (Mustafa Soysal) (edited)
My car died slowing down...I disconnected my EGR backpressure transducer
from the vacuum lead. Now my car is a little bit more stable at idle,
better gas mileage, most likely can't pass emisions. (Jeffrey Paul
Chojnacki) - note: others warned against disconnecting EGR; there may
have been a leak in the EGR system.
My 1986 Le Baron engine's CTS's connections had corrosion on them (a scan
tool showed that it took a long time to reach 180F and that it NEVER went
above 180F during highway driving); I opted to replace the CTS and
connector. Cold start problems went away and fuel efficiency improved. No
If you have hot restart problems which disappear after 10 seconds
of engine running, use tuner cleaner on the throttle body temperature
sensor's connector and see if the situation improves. (Bohdan Bodnar)
Dave says: try the basics. Replace the rotor ($6), distributor cap, wires
(silicone coated lifetime warranty name brand=$20 mail order!), and clean
and regap the plugs.