97 Intrepid runs rough at times

I have a 97 Intrepid that has had a recurring check engine light
problem that turned into a rough idle and intermittent rough running
problem. The oxgen sensor has been replaced as well as the intake.
The problem went away and has now resurfaced. When the engine is cool
it runs fine. After the day warms up and when I drive home, after 20 -

30 minutes it starts to lose power, the check engine light blinks and i

have to ease off and feather the gas to get it back. If i have to slow

or stop, it is so rough the car feels like it is running on half the
cylinders, and at times the transmission won't shift properly.

The fuel pump was replaced about 2 yrs ago.


It has 5 codes that all are cylinder misfires. P0305,P0301,P0303 etc

 

If the check engine lite flashes you are experiencing a cylinder misfire,
when was the last time the vehicle had a tune up with a good set of plug
wires?

 

The last tuneup was about a year to 18 months ago, but the wires and
plugs were checked in January when it was in the garage for this
problem. At that time they replaced an oxygen sensor that was bad and
the intake(plenum) on top of the motor.

 

I have 2 '97 Intrepids with one that runs a little rough at idle and
continually illuminates the Check Engine Light with a code 43 which is an
engine misfire code. After changing (swaping out with my other car) the
plug wires, ignition pack, I was still getting the light coming on.
Finally my mechanic buddy sprayed something on to the front portion of the
intake manifold and the idle cleaned right up (temporarily). His
recommendation is to replace the intake manifold gasket (which I have yet to
do).

Right now I have another problem with the other Intrpid that I will post
seperately.
Mark

 

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If your other one is the overheating one the intake manifold gasket causing
the rough idle may also be causing there overheating problem. The water
jacket on the cylinder head is next to the intake valve and will suck the
coolant into the engine causing low coolant and eventually an overheat
condition

Glenn Beasley
Chrysler Tech

 

In the morning the car runs fine and I drive for 35-40 miutes about 25
miles, most of them at highway speeds. In the afternoon once the air
has warmed up and after driving a few miles(5-8) miles the engine
starts to misfire and falter, losing power and speed. If l let off the
throttle and feather it for a few minutes, it smooths out somewhat or
you can put your foot into it and overpower it with rpms. Could bad
wires behave this way? It seems to me that it is more like a vaccuum
problem or some unit that behaves differently when warm than when cold.