Chrysler Repair: 1993 dodge spirit 2.5: stalls when decelerating with foot off the gas, straight blade screwdriver, exhaust gas recirculation valve

Question
the car stalls at an idle... but not all the time...it seems like when it idles to low is when it does it. ex. like when i have my foot on the brake and turning the wheel...and it only does it when its warmed up... at a stop light and running down the road or highway it runs great...

Answer
Hi Jon,
You can get some clues by doing a fault code readout using the ignition key:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light, which remains 'on', to begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat to be sure you have a consistent set of counts. Then group the counts in pairs to form 2-digit fault code numbers. The go to www.allpar.com/fix/codes.html for a code translation, or write back with the numbers for some direction as to what to do.
Another possibility when stalling occurs when you have your foot off the accelerator is that the exhaust gas recirculation valve is failing to close and thus hanging up slightly ajar. It is located behind the engine (between the engine and the firewall) and it is closer to the front of the engine so stand on the passenger side and look down and in behind the engine for the egr which has a pipe coming from the exhaust manifold to its underside and a pipe from it going to the intake. There is a vacuum operated round fitting on its top, and also a vacuum line going to an electrically operated valve closer to the engine, nearer the throttle body. Look under the round fitting (which is mounted on a saddle with openings for access to view) on the top of the valve where you will see a vertical rod with a slot in it which is the valve stem. Take a straight blade screwdriver and use the slot to lever the valve up against spring pressure and see if it is dropping back down due to spring's action and closing positively. Put WD-40 on the stem to loosen it up in that motion if necessary. Check to make sure the vacuum lines are all attached and not cracked. Then warm up the engine and observe the slot to see if it goes up when you rev the engine to 2500 rpm and then drops back down fully, closing the valve, when you let the engine go back to idle rpm. Make sure that the fully down position is really down because if it is not fully closing when you let go of the accelerator and coast that will cause the engine to stall. It may be that to get it to close you'll have to unbolt it and clean out the gas flow passage past the valve due to buildup of exhaust fumes in the valve as sticky crud deposit around the internal valve.
The other thing to verify is that the spark timing is set to 12BTDC with the coolant temp sensor's plug on the thermostat housing disconnected (the fan will come on when you pull that plug) and the engine warmed up. Those are the most likely causes for stalling on deceleration absent any other fault code.
Roland