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RE: 86 5kCSQ jerks when deacclerated

I saw another post on the decel shutoff valve ... I'e never run into
that one, but you could test to see if it was happening in your case by
not completely removing your foot from the throttle.  The decel bypass
is only enabled if the RPMs are above a certain value and the Idle
Switch is closed.  My thoughts were that the effect might be due to a
high effective compression since you are on boost.  This would be more
likely to be true if you quickly went from full throttle acceleration to
foot off the gas.  Normally the turbo engine isn't great for engine
braking due to the lower compression, but you can get a big spike of
deceleration when the turbo is angry ... I don't think the '86 has the
idle dashpot, so it is also possible for you to get a backpressure spike
in the turbo and t\intercooler when the throttle is closed under high
boost as well.  I don't know whether or not this will increase engine
braking though ...

Steve Buchholz
San Jose, CA (USA)

> ----------
> 	Summary of the problem would be 
> 	"Is hard engine braking normal to this car"
> 	Explanation of the Problem will be like;
> 	I am not sure if it is a characteristic of the beast or
> 	if there is something wrong. While in stop and go traffic
> 	(california), let's say I am in in a low gear, and I just
> 	took my foot off the gas pedal, without pressing the clutch, 
> 	the car has a sudden jerk. The jerk is so bad that I get 
> 	nervous that someone might hit me from behind ( bumper to 
> 	bumper traffic). I have been driving stick shift for last 
> 	20 or so years, and don't think that I have to press clutch 
> 	everytime I take my foot off the gas pedal. The lower the 
> 	gear the harder the jerk is.