Car dies in park when gas pedal pressed lightly

[ibgreezy]

Hello all,

I got an 86mcss, it is all stock. While the car is in park and in idle and I press the gas pedal lightly the car dies. If I press the gas a little harder it bogs a little before reving normally. The cap, rotor, plugs, wires, and fuel filter are all new.

Also there was a small vacuum line that was rigid not as flexible as the other vacuum lines that was tie wrapped to the passenger side spark plug wires that melted on exhaust manifold shield thing (the part where the air cleaner duct goes to). It looks like one side of the vacuum line goes to a diaphram looking thing on the passenger side. Anybody know what the vacuum line is or what it controls? Thank you.

 

[CWPottenger]

Which engine do you have?

 

[ibgreezy]

The stock 305 h/o.

 

[ibgreezy]

The vacuum line looks like it goes to a diaphram, from the diaphram to a damper linkage on the exhaust.

 

[87BlazeLS]

If you have a vacuum leak at this hose could be your problem. Plug the hose end and see if the problem
goes away. Make sure you plug it correctly. With the engine running if it's leaking you will feel suction
on the hose coming from the motor. Put a bolt or screw in the end and see if it gets better.

 

[pontiacgp]

sounds like the accelerator pump needs to be replaced

 

[87BlazeLS]

If acc pump is bad you can check by removing the air cleaner top and open the throttle linkage by hand
looking down in the carb you should be able to see it squirt gas. If not then yup acc pump.

 

[Bill Creller]

The plastic hose & diaphragm you mentioned sounds like the EFE valve on the bottom/rear of the right exhaust manifold.. It's supposed block the exhaust flow a bit so that some of it passes through the passage under the carb. EFE just means Early Fuel Evaporation. It's usually controlled by a vacuum valve on the coolant cross-over on the front of the intake..the valve moves as coolant warms up...
The stumble when the pedal is pushed lightly could be like mentioned..the acceleration pump in the carb

 

[ibgreezy]

Would the acceleration pump be part of a carb rebuild? Thanks for all the help guys!

 

[pontiacgp]

I've changed mine without doing a rebuild. If you are going to change it without doing a rebuild you'll need to get new horn gasket and lightly coat the new gasket with lithium grease so if you ever have to remove the horn you'll be able to reuse the gasket. If you are going to rebuild it then do some search cause it's an electronic quadrajet