My 07 XC70 is run good, but it seem lost the pepy when accellerating; Here the problems: I replace the reg. air filter with an cool air induct filter then pour a botle of fuel system and injection cleaner in full gas tank, it was run good untill I got on the highway at 70+mph suddenly the engine rumble and hesitated, but just for a second, then it run OK again untill we got to destination about an hour drive, couple hrs latter I started the car, it started right up, but just for 15-20 seconds it shutted down, I kept restart, it's start but did not hold the Idle, I have to rev. the engine up to 3K rpm for couple of minute then the engine hold the idle and we able to return home, the problem still repeat since. the check engine light is on, I scan with OBDII it said engine ran rich, and miss fire cyl. 1&2, I check the spark plugs and ign. coils they OK, replace the fuel injections, I start the car next morning, still not hold the idle till engine warm up, once it ran it's ran good, but sitll feel lack the pepy of turbo. I have been work with my cars for a long time, but this is the first car I had with turbo, so here are few questions:
1-How to tell if the turbo is not work properly?
2-Could it be a stuck butterfly in trottol body?
3-If the turbo is not run, can I re-route air intake to by-pass the turbo? The turbo air intake route is very long, if I use K&N air filter go dirrect to trottle body it will be much shorter
4-Will ECU relearn the air intake without turbo or I have to reprogram it(which I don't know how)

 

You have either a dirty throttle body or a failing VVT solenoid. Start with engine codes.

 

Thanks tony1963 can you tell me what is VVT solenoid and where it's located? Thanks again

 

The VVT solenoid is on top of the engine by the cam sprockets. A lot of people pull these off and clean them, but mostly the problem is that the coil on the winding has high ohms resistance making it unable to pulse and control the oil flow.

Start by checking for any engine codes.

You also could have an air leak in the turbo pressure line. Again, start with the codes.

 

Thanks Tony, you're right. The last code I got was "System too rich at idle."; That lead me to think something was not right with air induction system, I check the turbo: It's work and shuck the air in strongly, passed. Next I want to remove the turbo pipe on top of engine to check on the throttle body, looking down the S rubber hose; Lo and behold! The end of the hose at the inter cooler was came off half in half out, so I found the culprit, I put thehose back in and tighten it up real good start the engine and have a test drive: All is well! The idle is smoothly and quetly, engine pulled smooth and strongly on the highway, The problem's solved without pay a penny.

 

You will find this a semi-temporary solution. If you want to be done with this for the next 10 years, spend about $53 and get new turbo hoses for the two rubber hoses at each end of the turbo pipe.

Here's the items:

https://www.rockauto.com/info/64/262...OP_A__ra_p.jpg

https://www.rockauto.com/info/64/262...OP_A__ra_p.jpg

We always use the Gates hoses. Do not be tempted by the Uro parts as they are not durable.

 

Thanks Tony, I'll put one at the turbo end so it;s flex and high enough to remove the coils and spak plugs cover without remove the pipe.

 

Actually that's how they get damaged. Use a 7mm socket and loosen the fitting at the turbo and pull the pipe out so you don't damage the soft connection.

Of course, first remove those T25 torx screws on the manifold.