QuestionQUESTION: My 95 Concorde shakes badley when it hits 40 mph, then some days it runs smooth as silk. At times when I start it, it feels like all cylinders arent firing, then other times it runs great.When it is shaking badley from 40-55 Mph it seems to come out of it when I hit 60-65 . Any ideas ?
ANSWER: Hi Matt,
Use your ignition key to ask the engine controller for any fault codes that would reflect the possible cause of this:"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 verify an accurate count of the flashes. Then group the flashes in pairs in the order of appearance to form the 2-digit fault codes. Then either write back or go to www.allpar.com/fix/codes.html for a code translator. We can go from there for finding the likely cause.
Also, let me know the engine that you have in the vehicle.
Roland
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QUESTION: My 95 Concorde has the shakes periodically. Its a 3.5 and the code is reading 55. It comes and goes, when its idoling it feels like all cylinders are not firing and that is when it shakes badley specially when it hits around 40mph, Then other times there is no shimmy in it at all and runs smotth as can be. After reading I thought it may be a trirod or bushings, but that doesnt explain why it would shimmey while idoling. I have changed the fuel filter,PCV valve,and air filter so far.
AnswerHi Matt,
I would take a look at the exhaust gas recirculation valve which is located behind the engine near the air intake throttle valve. It is mounted in a pipe that runs between passenger side exhaust manifold and the air intake manifold. The valve is mounted horizontally and has a valve stem between its round vacuum actuator top and the body of the valve attached to the pipe, inside the flange that connects the two parts. The stem has a slot into which you can insert the tip of a flat-bladed screwdriver so as to lever the stem back and forth against spring action which should move freely and close tightly. If the stem seems to be sticky so that stem doesn't close all the way by spring action, then you can try spraying some penetrating solvent like WD-40 on the valve stem to freeup its motion.
If the valve is sticking slightly ajar it will make for a rough idle and poor acceleration such as you describe because the mixture is too dilute. It is one of the most common causes of this symptom. So see if you can find the valve and check/lubricate the stem. To check it in motion you can rev the engine from idle to 2500 rpm and back to idle and watch to see if the valve stem moves freely in both directions to the extreme open and closed positions. It may be that the interior of the valve is cruddy so that might require that it be unbolted from the pipe where it it attached and cleaned. But chances are good it will only be a sticky stem. Feel free to write back with the results and other questions you might have.
Good luck on the troubleshooting.
Roland
