Re: Need Help

["Paul C. Waterloo" <74543.407@CompuServe.COM>]

> From: Escoses@aol.com
> Date: Mon, 13 May 1996 15:41:27 -0400
> Subject: Need Help
> 
> I have a 1991 20V90Q with a manual tranny and over the last month or so I
> have noticed a marked deterioration in my gas mileage: From an average 23-24
> mpg down to 19-20mpg with no change in driving habits, distances, speeds,
> etc.
> 
> The engine starts up fine from cold (75 F overnight) and idles at 800 RPM as
> it should. However, when I drive it for a while and  get it up to operating
> temperature, if I take my foot off the gas, like at a traffic light, the
> engine will stall most of the time. If it doesn't stall, it will surge from
> 200 RPM up to about 1100 RPM and back down again a couple of times before it
> stabilizes at 800 RPM. Mostly, however, it will stall. Sometimes, when this
> happens I will smell fuel, briefly.
> 
> Sometimes, about the only way I can keep the engine running when I come up to
> a stop light is by doing some heel and toe work. Tweaking it once or twice
> usually stabilizes the engine.
> 
> I have no problem when driving, except for the gas mileage, the engine runs
> fine. The engine incidetally has about 94K miles on it and all this started
> after I disconnected the ground strap on the battery to do some wiring work.
> Coicidence?
> 
> What's going on? Is it a failing fuel pump, regulator, etc.? Is it a bad idle
> stabilizer valve?
> Leaking vacum connections? Is it something worse like the fuel injection
> control unit? The fuel filter is new and the plugs look clean.
> 
> If anybody has had a similar experience, I would appreciate their help and
> advice.
> 
> TIA,
> Graham

I would definetly look at the rubber hoses that connect the idle stablizer valve
to the throttle body. You could very well have one that is cracked (look at the
downstream side of the valve). 

Start the car and then go under the hood and feel around the rubber hoses. Bend
them and make sure they don't leak air. If they do, you will defintely hear/feel
it.

Paul Waterloo
Colchester, CT

87 5KSQ