Diagnose engine misfire problem
 

This is a Town and Country 2003 van (3.8L). It ran fine then the next
day when I started it, it didn't run smoothly. The car shakes a lot.
Check engine line came on and I smelt gas. So, I shut down. I read
the code and it has 3 codes. 1 code is random engine misfire. The
2nd code is cylinder 3 misfire and 3rd code is cylinder 4 misfire.
So, I disconnect batter and replace all the spark plugs with a
platinum (2 prongs) spark plug. The service manual says platinum type
is the one, but the old spark plug from the car is coper type (I
believe, based on the look of it). Put everything back and starts.
The car no longer shakes, but the engine is not smooth. I plugin the
code reader and get a check engine light is on, but no code. So I
press clear on the code reader, which said it can't do that. But read
again, there is no code and check engine light is off.

I unplugged the wire to the spark plug of cylinder 4, and plugged it
into a test spark plug. Started the engine. Sparks came out of the
thing.

Plugged back and I drove around a couple block to see if the problem
goes away. Engine still rough, not smooth, and still no code when
read. I no longer smell gas.

How do I go from here for finding out what the problem is? What's the
most likely cause for this? Fuel system? What would a mechanic do
from here?

Diagnose engine misfire problem
 

if you used bosch spark plughs get rid of them they foul out real easy

vd wrote:

> This is a Town and Country 2003 van (3.8L). It ran fine then the next
> day when I started it, it didn't run smoothly. The car shakes a lot.
> Check engine line came on and I smelt gas. So, I shut down. I read
> the code and it has 3 codes. 1 code is random engine misfire. The
> 2nd code is cylinder 3 misfire and 3rd code is cylinder 4 misfire.
> So, I disconnect batter and replace all the spark plugs with a
> platinum (2 prongs) spark plug. The service manual says platinum type
> is the one, but the old spark plug from the car is coper type (I
> believe, based on the look of it). Put everything back and starts.
> The car no longer shakes, but the engine is not smooth. I plugin the
> code reader and get a check engine light is on, but no code. So I
> press clear on the code reader, which said it can't do that. But read
> again, there is no code and check engine light is off.
>
> I unplugged the wire to the spark plug of cylinder 4, and plugged it
> into a test spark plug. Started the engine. Sparks came out of the
> thing.
>
> Plugged back and I drove around a couple block to see if the problem
> goes away. Engine still rough, not smooth, and still no code when
> read. I no longer smell gas.
>
> How do I go from here for finding out what the problem is? What's the
> most likely cause for this? Fuel system? What would a mechanic do
> from here?

Diagnose engine misfire problem
 

Unfortunately, I think that's what I got. However, I don't think I
can return it, because I already use it. Do you think I can do that?
Do you think that it's bad already that causes the current problem?

On Jul 31, 7:24 pm, philthy > wrote:
> if you used bosch spark plughs get rid of them they foul out real easy
>

Diagnose engine misfire problem
 

"vd" > wrote in message
oups.com...
>
> This is a Town and Country 2003 van (3.8L). It ran fine then the next
> day when I started it, it didn't run smoothly. The car shakes a lot.
> Check engine line came on and I smelt gas. So, I shut down. I read
> the code and it has 3 codes. 1 code is random engine misfire. The
> 2nd code is cylinder 3 misfire and 3rd code is cylinder 4 misfire.
> So, I disconnect batter and replace all the spark plugs with a
> platinum (2 prongs) spark plug. The service manual says platinum type
> is the one, but the old spark plug from the car is coper type (I
> believe, based on the look of it). Put everything back and starts.
> The car no longer shakes, but the engine is not smooth. I plugin the
> code reader and get a check engine light is on, but no code. So I
> press clear on the code reader, which said it can't do that. But read
> again, there is no code and check engine light is off.
>
> I unplugged the wire to the spark plug of cylinder 4, and plugged it
> into a test spark plug. Started the engine. Sparks came out of the
> thing.
>
> Plugged back and I drove around a couple block to see if the problem
> goes away. Engine still rough, not smooth, and still no code when
> read. I no longer smell gas.
>
> How do I go from here for finding out what the problem is? What's the
> most likely cause for this? Fuel system? What would a mechanic do
> from here?
>
Take the vehicle out and get it hot, going about 40mph come to a coasting
roll for about 20sec and then check to see what the engine fault code says.
Chances are the plug wires are bad. The adaptive numerator may have to be
learned in order to detect what cylinder is misfiring. and coming to a
coasting stop will learn it

Glenn Beasley
Chrysler Tech

Diagnose engine misfire problem
 

I took the car out this morning and drive it to hot. Also, I drove it
at different speed, including highway, 45mph, and slow with many
stops. I have tried to coast many times, but had to use the brake
eventually because I didn't have the distance, and morning traffic.
However, the engine light does not come on. I'll read the code
tonight. When the engine is hot, it seems to run more smoothly.
However, when comes to stop, it is still not smooth, but not as rough
as when started.

On Jul 31, 8:23 pm, "maxpower" > wrote:
>
> Take the vehicle out and get it hot, going about 40mph come to a coasting
> roll for about 20sec and then check to see what the engine fault code says.
> Chances are the plug wires are bad. The adaptive numerator may have to be
> learned in order to detect what cylinder is misfiring. and coming to a
> coasting stop will learn it
>
> Glenn Beasley
> Chrysler Tech

Diagnose engine misfire problem
 

I got the check engine light on again. This time, the code is
cylinder 3 misfire. How would I go about to trouble shoot this? I am
thinking of measuring the resistance of the cord connecting to the
spark plug. Is this the way to do it?

Diagnose engine misfire problem
 

"vd" > wrote in message
oups.com...
>
> I got the check engine light on again. This time, the code is
> cylinder 3 misfire. How would I go about to trouble shoot this? I am
> thinking of measuring the resistance of the cord connecting to the
> spark plug. Is this the way to do it?
>

By disconnecting the battery you erased the learned adaptive numerator
memory and all the rest your monitors. Therefore it would not show you
what cylinder was misfiring. That's why you should not do a battery
disconnect!! More then likely you have a plug wire that is causing the
problem. you can either go out and purchase a good set of wires to see if
that takes care of the problem or try switching number 3 wire with number 4
wire. If the misfire now shows number 4 cyl misfiring then you know for sure
the plug wires are at fault.

Glenn Beasley
Chrysler Tech

Diagnose engine misfire problem
 

man i can't tell you how many people come to my shop and they say they just
did the plugs themselfs and 95 % of the time they are bosch
our first question to the customers is did u use bosch plugs!second is plug
wires that failed esp. on gm cars

vd wrote:

> Unfortunately, I think that's what I got. However, I don't think I
> can return it, because I already use it. Do you think I can do that?
> Do you think that it's bad already that causes the current problem?
>
> On Jul 31, 7:24 pm, philthy > wrote:
> > if you used bosch spark plughs get rid of them they foul out real easy
> >

Diagnose engine misfire problem
 

or since you changed plugs you could swap plugs first

maxpower wrote:

> "vd" > wrote in message
> oups.com...
> >
> > I got the check engine light on again. This time, the code is
> > cylinder 3 misfire. How would I go about to trouble shoot this? I am
> > thinking of measuring the resistance of the cord connecting to the
> > spark plug. Is this the way to do it?
> >
>
> By disconnecting the battery you erased the learned adaptive numerator
> memory and all the rest your monitors. Therefore it would not show you
> what cylinder was misfiring. That's why you should not do a battery
> disconnect!! More then likely you have a plug wire that is causing the
> problem. you can either go out and purchase a good set of wires to see if
> that takes care of the problem or try switching number 3 wire with number 4
> wire. If the misfire now shows number 4 cyl misfiring then you know for sure
> the plug wires are at fault.
>
> Glenn Beasley
> Chrysler Tech

Diagnose engine misfire problem
 

That's an excellent suggestion. I'll try that out. I was working for
the whole weekend. The cylinder 3 is inside, which means I have to
take the wiper rack out. I'll try to get that done as soon as
possible. Thanks.

On Aug 5, 1:02 pm, philthy > wrote:
> or since you changed plugs you could swap plugs first
>