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Topic: Need Help! (Read 2747 times) previous topic - next topic

Need Help!

Hey guys,
This has nothing to do with Cougars or Thunderbirds, but I need some help with my brother's car.
It's a 1996 Chrysler Concorde LXi. It has the 3.5 V6 with 78k miles.
The car recently showed some very strange habits.
It has violent shakes while it is idling, especially when it's in gear and the brakes are held. The engine rocks back and forth in the bay.
While driving, it stumbles and shakes horribly, almost knocking itself into stalling. Depending on the position of the throttle, the shakes will vary in intensity.
Also, there is a strong smell of carbon or something while it's running. It smells like fireworks, anybody know what this is?
He had it serviced last week and this shop is notorious for screwing things up on our cars.
I'm thinking it's emissions or electronics related.
Any ideas???

Thanks!
[SIGPIC][/SIGPIC]

Re: Need Help!

Reply #1 –
Emissions may be the key.  Plugged catalytic convertor(s) is my guess.

Re: Need Help!

Reply #2 –
I'd have to agree with Ifixyawata.  As far as the engine rocking back and forth in the bay, I would check my motor mounts too.  Every other symptom points to a clogged convertor.
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!

Re: Need Help!

Reply #3 –
Thanks for the replies.
The thing is, it just started acting like this today.
He had the rack & pinion replaced last week and I thought they may have pinched a wire or forgot to reconnect something. But then again, why would it start acting like this one week later?
In any event, it isn't throwing any codes, so I didn't get any help there.
If the cats are plugged, will the exhaust get unusually hot while running?
Thanks again for the help.
[SIGPIC][/SIGPIC]

Re: Need Help!

Reply #4 –
Yeah, it should get hot, especially from the cat's forward.  My friend had an old nissan beater truck that he used on the farm and it would run good till it got hot and then die.  We found out what the problem was after he drove it back one day and the inside of the cat convertor is glowing red.  Cutting it off solved the problem, but that is not a good solution in your case.

Re: Need Help!

Reply #5 –
What about the MAP sensor? hose and connector?

Re: Need Help!

Reply #6 –
What about the MAP sensor?

Engine shaking the hell out and trowing Blck Carbon smoke mean you have a bad Air-Fuel calculation....

There is a good chance the MAP sensor (Front of the intake Manifold) may be bad, defective, unplugged, broken vacum hose or maybe a broken wire there...

Also check your O2 sensor connection, wires

Re: Need Help!

Reply #7 –
Quote
If the cats are plugged, will the exhaust get unusually hot while running?


Yeah,  plugged converters will get very hot. 

Quote
What about the MAP sensor?
.


As new as it is it probably don't have one.  Although I have seen other cars that have had both a MAP and MAF.  (and no it wasn't being used as a Barro sensor either)

Re: Need Help!

Reply #8 –
I'd look for a misfire - bad plug, wire, coil pack, injector, etc. The timing could be off as well (the belt or chain may have jumped a tooth)
2015 Mustang GT Premium - 5.0, 6-speed, Guard Green - too much awesome for one car

1988 5.0 Thunderbird :birdsmily: SOLD SEPT 11 2010: TC front clip/hood ♣ Body & paint completed Oct 2007 ♣ 3.55 TC rear end and front brakes ♣ TC interior ♣ CHE rear control arms (adjustable lowers) ♣ 2001 Bullitt springs ♣ Energy suspension poly busings ♣ Kenne Brown subframe connectors ♣ CWE engine mounts ♣ Thundercat sequential turn signals ♣ Explorer overhead console (temp/compass display) ♣ 2.25" off-road dual exhaust ♣ T-5 transmission swap completed Jan 2009 ♣

Re: Need Help!

Reply #9 –
It should have a Map sensor most newer Mopars are speed density
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!

Re: Need Help!

Reply #10 –
Quote
The timing could be off as well (the belt or chain may have jumped a tooth)

thats definatly something to check, im not sure about the late model mopars, but the 2.2's would sometimes run like that if they skipped a tooth or 2
It's Gumby's fault.

Re: Need Help!

Reply #11 –
if it has something to do with the a/f mix, maybe the o2 sensors?
 

Re: Need Help!

Reply #12 –
Thanks for all the help, fellas! I was able to eliminate some of the possible problems, but it's still running terrible.
I recently learned how terrible the cars are on the LH chassis (LHS, New Yorker, Intrepid, Concorde).
It's a beautiful car, but very unreliable.
We're just going to take it back to the shop and let them figure it out... after all, they were the last to have their hands on it.
Thanks again!
[SIGPIC][/SIGPIC]