[IanH]

VQ hot soak power loss problem on re-start after 30 minutes to 1 hour.
This has happened only 5 or 6 times in 3 years but may be getting worse.
First happened under warranty at 25,000 miles 1 yr old, and drove straight to Nissan Dealers service, where they told me to shut it off.
Then it re-started fine, and no codes.
Yesterday I re-started, had the same symptoms and pulled over and re-started, problem did not go away until I got to where i was going and parked and came back. (2003 now with 65,000 miles)
This may be why the original owner sold this at 1 yr old !!!
All ideas and suggestions welcome.

 

[IanH]

Any ideas ?

 

[desdeleo]

Is it idling normal during the power loss? Any loss of coolant or signs of oil in coolant? Oil consumption is still normal?

 

[desdeleo]

Have you checked your fuel pressure? Had a similar problem on my truck but wouldn't start when hot. No problems staring when cold. Changed the fuel pressure regulator and problem vanished. Turns out the diaphragm was damaged. Sorry cant be more of a help.

 

[IanH]

Thnaks for your input. I will check the fuel pressure.
Was it a problem all the time or just once every 6 - 9 months ?
For instance its ok when i stop for gas, never given a problem then, only when left for 30 - to 60 minutes.

 

[desdeleo]

Well it was all the time but only when engine was up to temp then cut off for a hour till about 3hrs. But no problem starting after fillup or a quick stop of a half hour or so, And after 5hrs of cooling down no problems.

 

[IanH]

Humm, sounds similar, I didn't answer your other questions,
No other problems, no oil loss, coolant etc.
Yes seems to idle ok, when you accelerate its got no power and a bit jerky. runs up to 4000 uneven running, jerking a bit, very slow accel, and then shifts
Runs a bit better on very light throttle opening ....

 

[IanH]

Since this happens so infrequently i think i will have to plumb in a pressure gauge semi permanently, any suggestions, not checked fuel pressure on an injected engine.

 

[desdeleo]

Well installing a fuel pressure gauge is easy. all u need is a t fitting a pressure guage for fuel injected engine(higher pressure)and some hose barbs and some fuel line clams. Forgot the size of the fuel line I can look that up for u. The upper line leading to the fuel rail is the supply and the lower hose is the return line. I will try to post a pic where u can see my fuel pressure guage install.

 

[IanH]

Yours is silver same as mine !! nice picture with the fishing rods !!
Thanks. I will look at mine and get the pieces.
And yes you may be right, it may take more than 30 minutes to give problems but it is not all the time. I suspected the power valves or the swirl valves might not be opening, but fuel makes more sense because it does buck and run uneven with open throttle.

 

[IanH]

Solved !!!

Solved !!
Anyway I think so.
The dealer service department lied !!
Had to buy a code scan for my Lexus. after Lexus fixed just after the pathy had another funny turn, I hooked up the scan gauge and there were "pending codes" three or four of them. cleared them and waited for another funny turn. Took a year, pending codes was for bank two cam sensor.
While I am looking this up it had another funny turn and light came on for the first time in 9 years. Yes bank 2 cam sensor. clearly getting worse.
So replaced both and for rest of the summer no more problems.
lessons learned.
1) Don't EVER believe the service people when under warranty.
2) Pending codes matter so if you are having issues get the codes read including the pending codes.

Yes I did check the fuel pressure, gauge is still installed. Not the same problem.

In first post it should say 2008 and 65 K
This started the first summer I had the car, 2004, 18 months old and about 30K, Problem occurred in summer Only !!!