I bought a used x-trail with a QR20DE engine about a year and a half ago and I ran it with the oil and spark plugs which came with it for about two months and then decided to do a complete oil change and put in new spark plugs, brakes, radiator coolant etc.

As soon as this was done I noticed the performance of the vehicle was drastically reduced with an acceleration flat spot or hesitation.After time this became drastically worse and now it stalls when you are slowing to a halt or when turning to take a corner since it idles down and then stalls.

I have had it diagnosed many times and I have read the CD manaul for the T30 Model and the manual says that when you do a service and spark plug change that you have to get the ECU to reset its settings and then the electronic service is complete.

The Technicains here are saying that the Vehicle will sense the change of electronic parts and reboot the ECU itself. They have the idea that once there are no error codes or warning lights on the instrument panel there is nothing wrong with the vehicle.:screwy:

The vehicle according to the manual seems to be driving in limp mode and its getting worse.

Is there any way for me to carry out a manual ECU reset via the fuses or the battery terminals cos (because) I had a fantastic vehicle to drive now its a chore to drive it.:banghead:

Does anyone know where i can get a good but not too expensive diagnostic machine that will be able to clear any error codes on the X-trail and I will be able to do the service of the vehicle as well?:shakehead

I really hope there is a X-trail Guru on this forum cos I really need some help on this matter cos the x-trail (besides my problem) is a great vehicle to drive on and off the roads of my Caribbean island,Trinidad & Tobago.:grinyes:

Hey,
What spark plugs did you use?? I would really recommend the iridium spark plugs from NGK. Awesome performance and longer life.

To reset the ECU, you can either disconnect the battery for more than five minutes OR follow the guide on this link:
http://com1.runboard.com/baustralianxtrail.fqa.t194

I also suggest using genuine Nissan radiator fluid, as the coolant sensor responds better with the correct coolant. I also suggest you change your fuel filter as it may have picked up a bad batch of fuel along the way.

Let me know how you go and I will get back to you on a price for a diagnostics machine. Me and a few friends are working on a LCD display that will constantly output all ECU data to the user.

I'm using the original Nissan spark plugs that came with the vehicle(cant remember the exact name).The gas filter is located in the tank and it is part of the fuel pump and has been checked and cleaned.It is not a separate fuel filter that can be replaced.

My type of vehicle's ECU cannot be reset by taking off the battery terminals for five minutes as suggested but at least fror 24hrs and this has been done to no avail.

My CD Manual talks about reseting or re-calibrating the Vehicle's ECU (via the use of the diagnostic machine) by reseting it after you have done the normal mechanical tune up which is change oil,coolant,spark plugs & clean injectors etc.

The diagnostic machines and technicians do not know how to use their equipment because once there is no warning lights on the instrument panel they assume that the vehicle is working properly.

That's why my friend; I am having a problem and thats why I'm looking to source my own diagnostic equipment so that I can take care of my vehicle myself and not have to depend on people who are playing with my expensive vehicle at my expense.

Keep me in informed of any other idea you may have about my problem.
Thanks again.

Your spark plugs would be the problem here... They should be replaced every 20,000Km or 12,000miles. I would thoroughly recommend using the iridium plugs when you change them. Better spark and longer life!!

Also check your air filter, they are common for restricting air flow and causing the problems you describe. Make sure the air-flow meter wiring is correctly pluged in

The ECU WILL reset by disconnecting the battery, they have no long term memory without power but will keep the factory programmed settings. The diagnostic machine actually uses software to perform a power cut to reset the ECU so the clock/stereo do not need to be programmed.