I have a 1996 LHS with 100,000 miles. Check Engine light recently is active and find the engine idles rough. I followed the instructions to get the diagnostic codes from flashing of check engine light for more info about the problem and read 12, 43, 55 which I believe 43 indicates the problem. From information I've found online this could mean one of the following:


- Peak primary coil current not achieved
- Cylinder misfire
- Problem in power module to logic module interface


My local mechanic diagnosed this further to be a problem with cylinder #5 misfire and suggested that I first try a container of fuel injector cleaner to see if it clears up the problem. If not the repairs are going to be more costly. After running through a full tank of gas I still have the problem.


Anyone have any ideas?

that is odd i have a 1997 lhs and it has been acting ruff idling high i talk to a friend of mine he changed the plugs and wires well it poped a code mis fire cylinder 1 well i took it to a shop it was a oxgen sen. i replaced it well one of three but it coded the one on the right side of motor so it cleared the code but still is actin ruff well it tripped again this time i had it scanned and it said mutiple misfire cyl 5 just like what you said . i replaced the fuel injector but it still seems ruff even though the code is off did you ever find out what it was are you still haveing this problem?

Problem turned out to be a leak in the intake gasket. Replaced it and problem solved. Runs much better now.

Good call fryebago, Intake Gasket leaks are a common occurance on the 3.5 Liter Engines, I owned a Concorde and currently a 94 LHS and had to replace the Intake Gaskets on both of them. The best way to verify the leak is to remove the 4 torx head screws holding the plastic cover on the intake Plenum and take a spray can of Carburetor / Choke Cleaner with the extension tube inserted on the spray nozzle and lightly spray (Don't overdo it!) around in the areas of the plenum to manifold gasket, Manifold to Head Gasket and Injector Gaskets while the Engine is idling, if the Engine idle smooths out or the idle raises slightly then there is your leak.

to all concerened chrysler idle problem !!!! high idle runs rough !
I just went through all the stuff related to fixing this problem. talking to all the people i could find, reading books and surfing the web. now that i have found this site it is to late I found the problem on my own and after spending lots of money doing just what many so called experts told me to do.
plugs wires all kinds of high$ relays and sensors. the intake manifold gasket was shot on # 5,6
I am putting it all back to gather and will post my results

swapped out intake manfold gaskets < runs great now !!!

My 94 LHS has a miss I will try that too.

I have a 1994 LHS that runs ok for the first 5 minutes every morning then begins to idle rough and miss. I hooked it up to an OTC Genisis which found no trouble codes and diagnosed everything as ok.I took a greenlee 115v voltage tick and it would lite up and beep when touching the three RH plug wires but would give no signal on the three LH plug wires. Would this be the coil or a bad signal coming to the coil telling it when to fire?
Thanks, Dennis