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Ask sprinkles08 Your Own Question
sprinkles08, ASE Certified Technician
Category: Chrysler
Satisfied Customers: 22979
Experience:  ASE Master & Advanced level certified, Chrysler Master Certified, Trans and Hybrid Specialist
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96 concorde LXi 3.5 L 125 000 km (that's 80 000 mi), rough

Customer Question

96 concorde LXi 3.5 L 125 000 km (that's 80 000 mi) , rough idle (sort of comes and goes away), sometime dies at idle - never during normal drive, sometime slight "hesitation" with throttle just above idle and slow drive 40 km/h. Used Mopar injector cleaner about 6 000 km ago, replaced spark plugs 6 000 km ago (checked gaps before installing), recently cleaned up both throttles twice, replaced PCV hose, recently checked PCV valve (rattles when shaken), PCV valve sucks air when hose disconnected, replaced PCV hose with new one, replaced ignition switch with new one, replaced idle air motor with new one bought form Chrysler dealer (no shit around pintle seat). Sometime engine accelerates slightly when driving around 40 km/h.
No hard starts, just one turn of the key, recommended 89 grade gas used, engine oil change every 3 500 km.
What is it ? EGR system ??
Jacek *********@*****.***
Submitted: 1 year ago.
Category: Chrysler
Expert:  Wayne Crawford replied 1 year ago.

Hello. My name is ***** ***** I will be helping you today.

Have you checked the PCM for trouble codes?

Customer: replied 1 year ago.
from the flashing CHECK ENGINE light.
code 12 - the battery was disconnected during last 50 start ups
code 55 - end of codes
Expert:  Wayne Crawford replied 1 year ago.

Is there any way you can run it by an autozone or something and have them check it for codes? Im expecting to see a lean code and possibly misfire codes.

Customer: replied 1 year ago.
Will try to borrow from my friend had held scanner.One more: when Idle Air Motor disconnected the engine does not slightly accelerate "by itself" to 1500/2000 rpm
Expert:  Wayne Crawford replied 1 year ago.

Sounds good. Let me know what you find.

Customer: replied 1 year ago.
Found emission test done a year ago at 118 240 km , shows (I think) very low HC and extremely low CO - my guess is you might be right talking about lean mixture and misfire. The test was the "new" type of test, the car was not put on the rollers. I will try to find someone with a 5 gas analyser. Will also have to check the fuel pressure at injector rail. The fuel filter was replaced about 15 000 km ago.See attached file emission resultsJacek
Expert:  Wayne Crawford replied 1 year ago.

So you werent able to check the codes with a scan tool?

Customer: replied 1 year ago.
62; So you werent able to check the codes with a scan tool? <Not yet.Jacek
Expert:  Wayne Crawford replied 1 year ago.

OK. I will be standing by when you do get the codes checked.

Customer: replied 1 year ago.
Checked by mechanic (I was watching over his shoulder). The tool he was using was something called "Solar Edge" with touch panel display. No codes at all. Fuel pressure 42 psi idle/not running (witnessed by myself). Pressure held when not running.Would like to add: around 2006 at about 60 000 km I replaced PCM with new one bought from Chrysler. I installed it myself. The dealer said if I had trouble running I should come beck to have the PCM reprogrammed. Never went for any PCM reprogramming. Reason for PCM replacement - the radiator cooling fans were always on , even when cold and A/C off.
Expert:  Wayne Crawford replied 1 year ago.

Im not sure what is going on with it. I got an appointment in a bit here and wont be around till tonight so I am going to opt out and see if someone else has any ideas on it. Without you being able to access a scan tool Im not sure I can be any help to you. I need to get some information from the PCM and it would be a dreadfully long process if you keep having to go to a mechanics shop to get everything I need.

Customer: replied 1 year ago.
Forgot to add - today, engine hot, when getting green light and started to roll on the slight pressure on the accelerator there was a slight stumble - or hiccup (I drive like an old grandma - very easy on the accelerator).BTW, I do not understand your >> Without you being able to access a scan tool I'm not sure I can be any help to you ...<<I just returned from the mechanic who used the scan tool - see my previous post ...
Expert:  sprinkles08 replied 1 year ago.

Hello and welcome to JustAnswer!

There are quite a few things that could cause the engine to die but if no codes are setting and under the conditions you're having the issue, the first thing I'd suspect on this engine is the EGR valve hanging open.

How often does it run poorly or die?

Customer: replied 1 year ago.
Customer#62; How often does it run poorly or die? <It runs poorly (at idle) MOST of the time, but sometime the poor running goes away than it comes back and so on.
It dies sometime (preceded by worse and worse idle with engine shacking) but not very often (I know this in NOT a very precise answer). All this happens regardless of engine temperature, outside temperature, weather conditions and so on.Another thing: when engine is NOT running and a vacuum 10 in Hg is applied to the hose that goes to EGR valve from the HORIZONTAL outlet of the solenoid transducer, the vacuum does NOT hold. It takes about 5 seconds for vacuum to get to 0. Sounds leaking vacuum hose or cracked EGR diaphragm ??When engine is idling about 1.5 in Hg of vacuum applied to the above hose will kill the engine - which I believe is normal.The poor idle/dying "habits" do not go away when driving with the HORIZONTAL hose disconnected from the solenoid (no vacuum reaches EGR valve)
Expert:  sprinkles08 replied 1 year ago.

What i would recommend is making some blockoff gaskets for each EGR tube at the plenum and see if that allows it to run ok. These EGR valves would often leak which will cause what you're describing.

Customer: replied 1 year ago.
Sounds good - never thought about that !!!
Expert:  sprinkles08 replied 1 year ago.

Let me know how it goes!

Customer: replied 1 year ago.
I would like to answer to the last message I got from you just a few days ago:As recommended, with thin sheet metal I did blanked off both of the pipes supplying exhaust gases to the intake manifold and drove a couple of days. No difference.Than I unplugged wires going to the EVAP solenoid. The CHECK ENGINE light came on immediately but no difference to the engine - drove about 50 km (city drive). Plugged the wires back - CHECK ENGINE light went OFF.Then two days later CHECK ENGINE LIGHT came ON again. The "dancing key" procedure (ignition ON-OFF-ON-OFF-ON within 5 sec) revealed code 32, witch according to factory repair manual means either:- P0401 EGR system failure - Required change in air/fuel ratio not detected during diagnostic testor- P0403 EGR Solenoid Circuit - An open or shortened condition detected in the EGR transducer solenoid circuit.I am still driving with blanked OFF exhaust gases - so my guess that could have been P0401 - before I could get to my trusted mechanic who is equipped to read Generic Codes, the "dancing key" shows no more codes (except code 12 - battery disconnected during the last 50 cycles and code 55 - no more codes.Recently I partially removed insulation on the TPS middle wire to check TPS with digital voltmeter - 0.78 V at throttle closed to 4.00 V throttle fully open (repair manual says 0.5 V min to 4.5 V max). No "bad spots" during slow rotation of the throttle.So now I am going to do "wet test" - spraying the water mist over ignition wires and trying to see any sparking.Any other suggestions ?
Expert:  sprinkles08 replied 1 year ago.

Can you spray some carb cleaner under the intake with it idling and see if the idle changes?

Customer: replied 1 year ago.
I just used Mopar Combustion Chamber Cleaner - on both throttles - idle got worse particularly right throttle - limping even more, though may by I did not spray enough ? Anyway , rpm did not go up.
Outside temp around 25 C (90 F ?), sunny dry weather. Engine rear center mount and both rear "round" mounts replaced some 6 months ago. The engine shaking was even worse before mounts replacement.The other day when going up on the ramp from the underground parking the engine (cold) had a momentarily "hiccup" and with the corner of my eye I noticed the check engine light came on for a fraction of a second. The engine did not die and I continued on the ramp. This might explain code 12 retrieved during "dancing key" (code 12 means the battery was disconnected during the last 50 key ONs). I am still having both exhaust gases ports on the intake manifold blocked off as explained earlier.The "wet test" - spraying cables with "windex" mist did not show any change - mind you most of the ignition wires are covered by some plastic.Today the engine died twice before I had a chance to spray Mopar fluid on the throttles.NEVER had any problems to start or restart the engine. Turn the ignition key for 1/2 second and engine is alive - revs up to about 1500 than gradually goes down to idle.Sometime the engine has tendency to rev up by itself to about 1300 - 1400 rpm before coming down to idle speed.The idle speed is 1000 when transmission in P or N. After engaging the transmission the rpm drops to about 950 and the engine shakes less. As I mentioned before the engine mounts are O.K. The rpm is read off from the factory installed dashboard rpm meter.Jacek
Expert:  sprinkles08 replied 1 year ago.

Have you sprayed carb cleaner under the intake yet?

Customer: replied 1 year ago.
I have sprayed The Mopar stuff (see above) into the throttle bodies after removing the air supply duct - the sheet metal duct that connects air cleaner with both throttle bodies - is that what I should do - or perhaps I do not understand your instruction: >> ...carb cleaner under the intake ...<<What do you mean by >> ... under the intake ... <<If I do not understand you correctly then please explain in more detail - like for a dummyJacek
Expert:  sprinkles08 replied 1 year ago.
The intake bolts to the heads, the plenum bolts to the intake. Spray carb cleaner below the intake into the valley and see if the idle changes.