hallo everyone.
I m just new in the forum.
I want to share with you the issue of my jaguar s type 3000 v6 petrol year 2003
only when the engine is cold , for istance first start of the day, the engine has a random misfire.
than become normal around 60 deg.
of course i have already changed the spark plug also the M.A.F. is new
anyone can give me me an input?
thx a lot in Advance

 

Welcome to the forum.

Are you getting any fault codes, such as P0301 - P0306? Is the Check Engine light illuminated?

 

IMT O rings?

 

Also could be the early signs of a coil pack breaking down.

Are the spark plug wells dry?

 

yes sure p0300, random misfire.
after about 3 min. and about 60 deg. everything works well. i clear the code and for all day is perfect even if i park the car for 5/8h. it s related with cold wheter operation, in the summer it do the same in the morning but less less less.

 

yes wells dry

 

See page 29 here for code P0300:

http://www.jagrepair.com/images/Auto..._OBD_II_R2.pdf


The column at the far right has a list of possible causes. Since you are not getting a code specific to one cylinder, I'd suggest first checking fuel pressure, as that would affect all cylinders if out of specifications.

 

Thanks but i have this manual and i have already checked all this items. Everything are ok.

 

Okay, making some progress. Do you have a scanner, or access to one? Although it's not on that list, I'd suggest looking at the fuel trims. Some good info here on how to interpret the values to determine if you have any major vacuum leaks:

JagRepair.com - Jaguar Repair Information Resource

Maybe you've got a leak not bad enough to set other codes, but just enough to cause rough running when the engine is cold.

On a related note, these are not the exact symptoms you are experiencing, but check the resonator as seen in this thread:

https://www.jaguarforums.com/forum/s...solved-198690/

 

thx a lot for your help!
I think there is no leak because the short term e long term parameters are inside the range all the time, and even because i ve changed all gaskrts.
I m using an obd but i m not so happy. anyone can suggest me a good obd to buy for jaguar?