Re: Partial throttle problems

["jtrealty@xxxx " <jtrealty@xxxx>]

Well you seem to have a tough problem. Assuming all of the parts you 
replaced were the correct ones and that none of the new ones were 
defective and you did it correctly then we can also assume that the 
problem wasn't in any of the origional parts that you replaced since 
you haven't touched the problem. This is a perfect example of "replace 
till we fix it, we don't have to try to diagnose". At this point 
instead of testing all of the parts you replaced we could try to start 
troubleshooting directly unfortunatly the single most important device 
to use is something you don't have. You need to put a fuel system 
pressure tester on the system and observe the fuel pressures at the 
time of the symptoms. I will guess you have a 5 speed so the 
deceleration problem is caused by the rapid reduction of the 
throtttle. That may be normal depending on the severity. If you have 
an automatic then check out the vacum modulater and vacum lines to it. 
For the "light throttle" if you mean accelerating at part throttle 
then a possiblily is the control pressure regulater or the metering 
unit itself. Again a vacum leak will cause this and there are many 
connections under the intake manifold that you can't see. Another 
possibility is a problem in the fuel tank like a hole in the pickup 
hose, loose or incorrect baffles, kinked pickup hose etc. Sucking air 
at a critical time would lower fuel pressure and cause the car to 
"hiccup".Please post to the group so we can follow your progress and 
offer more suggestions and see what the cause was.One more thing to 
check, on the intake there are 3 adjusting screws, make sure they are 
all LIGHTLY seated in, they are not to be used to adjust idle, the 
idle motor does that. Also make sure the vent hose on the control 
pressure regulater is not kinked or plugged up.
David Teitelbaum
vin 10757




--- In dmcnews@xxxxxxxxxxx, "Chris C" <petleech@xxxx> wrote:
> We have a 1983 DMC with 84k miles on it, which we have refurbished. 
> Since we started the engine, upon deceleration or light throttle the 
> engine bucks and jerks.