Quick run down. Actually this may get long but I want to be as specific as possible so that I can get the help that I need. As I am new to g35 driver, I am not new to car forums in general and have had my G for over 2 years.

2003.5 G-sedan-AT

After noticing a gradual decrease in power and gas milage over the last few months, I decided to change out my spark plugs. I hadn't changed them since I bought the car and I just hit 100, 000 mi. Trust me when I tell you, I don't know how the car was running with those old plugs in it, they were bad. I repaced them with the same NGK platinum plugs that were in there. After removing the air box and tube, I noticed that the throttle body was filthy so naturally my first instinct was to clean it. I spayed it down with some TB cleaner that I had. I did not remove it, just opened the flap a bit, sprayed and wiped it down. I proceeded to change the plugs and put everything back together. I turned the car on and backed it out of the garage. Everything appeared to be normal at the time.

The next day as I was driving to work I noticed that the idle was higher than normal and the car was shifting weird when I was cruising while not aplying any gas. (shifting up and down from gear to gear) It also was jerking as it down-shifted through the gears. Also, my SES light came on. I assumed that I must have not connected something thus creating a vaccum leak. I checked everything when I got back home and everything looked ok. I did a search where I discovered that the TB on our cars are extremely sensitive. I learned about the re-learn procedures and ecu reset. I have done each about a dozen times. (using a stop watch) No positive result. Yesterday, I even changed out the pcv valve just on a hunch that I may have cracked the old one when I removed the hose to get to the plugs. I did all of the procedures again and the ecu reset as I had unplugged the battery over night and the SES light poped back on when I re-connected it.

After this time, I noticed that the idle had come down to the point where I could live with it and the car was not jerking as hard when down-shifting. I figured that I finally got it right. I assumed that maybe this is the way the car would have been running if I would have had some good plugs in it before. Well after driving it today, I can tell you the idle is right back up to 1100 RPMs and you can really feel it down-shift. I don't know what else to do. I know that it can't be healthy for my tranny and I don't want to be ripped off by the stealership. Can anyone help?

 

^You need to find out what that code is. That will help everyone diagnose.

 

^Thanks for a quick response. The code before I reset the ecu was P0507. It has not come back on. But the car is still idling high and jerking as it down-shifts.

 

Have you read this?
https://g35driver.com/forums/engine-...-g35-help.html

 

Thanks for your replies. I did read that and tried the different relearns many times with no success. I finally gave in and took it to the dealer. They had the car for about 45 minutes and everything is back to normal. The guy even advanced my timing that was retarded by a degree. Just a tip for any one with this problem. Go to the Nissan dealer, they charged me $95.00 and the Infiniti dealer wanted $135.00. It was very much worth it. The car runs like a new car. I wish I would just have took it there from the jump. I could have saved a lot of time.

 

Did they tell you what the problem was?