Part Throttle "bucking"...

["Eric" <ericp@xxxx>]

Hi Folks,
A few weeks back I posted a question based on my problem with my D 
having a "Deceleration Problem". Wow, thanks for all of your reply's 
especially that of DMCjoe.

Well, I've learned a lot since then - but not enough to solve my 
problem. But, I figured I'd repost what I've learned and maybe ask 
for some more responses to see if I can't get more enlightenment from 
others here that have more experience than I.

First, I have learned to better describe my problem as a "Part 
Throttle" bucking or severe hesitation problem. Because upon HEAVY 
acceleration - the problem does not exist. Nor does it exist during 
an idle or during level cruising (as long as you keep the lightest 
touch on the accelerator.

The problem does NOT exist when the engine is cold, or even cold-warm.
But gets worse as the engine comes up to temperature.

Also, based performing some diagnostics (thanks DMC Joe!- and the 
Bosch K-jetronic book) I have learned it is NOT: a vacuum leak, all 
of the vacumm hoses are now new, so is the vacuum thermal valve that 
sits under the intake. It is not the frequency valve, the O2 sensor, 
or the RPM relay. (By the way, if you have an oscilloscope handy - 
this makes this a breeze to test! Anyone nearby me in Clearwater is 
welcome to borrow mine if needed).

I believe I have it down to a specific area or circuit. I'm now left 
looking at a few components: The Control pressure Regulator, the cold 
start injector, or the (ugh) fuel distributor. 

The car is running VERY rich. (black, rich smeeling exhaust is 
obvious). It gives every symptom of a carburated engine that is being 
choked - having too much fuel or not enough air. Although, I'm 
reasonably confident the airflow sensor plate and those circuits are 
working well.

Knowing everything I've bored you with here - I'd be grateful for any 
more advise. 

Thanks
Eric Peterson
Vin# 5557
ericp@xxxx