: motor stumbles at slow idle



Street_Rod_Guy
08-24-10, 06:21 PM
I got a '96 Fleetwood.
Car runs good, (gets typical horrible gas mileage - 15 in town, 19 Hwy... LOL)
Anyway.. I have found that when it am stopped, the car runs and idles well.. As I ease down on the throttle to (say pull away from a red light or stop sign) it seems to have a slight stumble. Never dies,.. but I either usually pat the gas pedal, or just back off entirely.
Don't think it's anything "major".. just annoying

Anyone have any ideas what this is or what causes it..?? How do you fix it.
I thought about finding out how to idle it up just a touch.. but the gas mileage is bad enough already.. Any ideas or suggestions appreciated..

drmenard
08-24-10, 07:14 PM
On these cars the first thing I would look for is a bad plug wire....

Street_Rod_Guy
08-24-10, 07:21 PM
ok thats a starting point..

Just a question.. If a plug wire is bad.. wouldn't it 'miss'.... all the time. ?? :hmm:

SilverCoupe
08-26-10, 02:19 PM
Basic tune-up check maybe to start with. As mentioned, plug wires, Opti cap and rotor and the EGR diaphram gets tight, or the pintle end gets sticky. Caused rough idle on my 95 FWB, I sprayed it up few times w/ carb cleaner and silicone to ease the diaphram movement for the EGR. Just some things to check. OHH and also maybe clean up the throttle blades inside, they get dirty and do not close all the way for the proper air mixture at idle.

Street_Rod_Guy
08-26-10, 02:30 PM
OK.. sounds like all things I can handle.
I should of mentioned this is the big motor that came in the Corvettes.. Probably doesn't matter as far as my issues however.

HUF
08-27-10, 02:05 AM
Basic tune-up check maybe to start with. As mentioned, plug wires, Opti cap and rotor and the EGR diaphram gets tight, or the pintle end gets sticky. Caused rough idle on my 95 FWB, I sprayed it up few times w/ carb cleaner and silicone to ease the diaphram movement for the EGR. Just some things to check. OHH and also maybe clean up the throttle blades inside, they get dirty and do not close all the way for the proper air mixture at idle.

+1 Stuck open EGR valve can do that. Carb cleaner can eat up the diaphragm. First make sure the diaphragm is in tact. Pull of the vacuum hose, press the diaphragm as far as you can and block the vacuum port. If it moves back, replace the EGR valve. If the diaphragm holds vacuum, remove the valve (two easy bolts or nuts), clean with carb cleant while holding so that the cleaner cannot get to the diaphragm. If the gasket got damaged, replace it with new one before reinstalling the valve.