2005 Pathfinder erratic idle

[hayesmarti29]

Hello Everyone,

I'm having an issue with my '05 pathfinder that has me very puzzled. I'm trying to avoid the dreaded dealer service center visit but I feel like that will be my only option. I recently changed both valve covers (due leaks), while I was there, I decided to go ahead and install new spark plugs and also upper intake gasket because the vehicle was having some erratic idle issues. I also decided to replace the throttle body gasket that goes between the intake and TB. After all the work, It started idling around 1,100 RPMs. I took it to Nissan for them to correct the high idle issue, now it idles around 625 rpms with AC off or 725 when AC in on (both are a little rough idles). The major issue starts when I press the gas pedal. When I press the pedal, sometimes it causes the idle to jump so high that the belt squeals to a high pitch from the high rpms and it sounds like the engine from a 18 wheeler. At the same time its very sluggish with noticeable drop in horsepower. While driving for a bit, it goes away and sluggishness goes away and you notice the increase in horsepower right away. Other times, just the opposite happens, it starts off driving fine, then the idle jumps to nearly 2,500 rpms, gets sluggish and belt starts to squeal because the engine is revving so high and the 18 wheeler sounds returns. The odd part is that I'm not getting any error codes. This happens off and on many times while I'm driving it. I thought it was a vacuum leak somewhere but I can't seem to locate it. I've done the smoke test and no smoke comes out of anywhere. I've replaced the throttle body, the upper intake and all of the gaskets.

If anyone has any suggestions I'd gladly welcome them. Next stop is Nissan dealer which I'm sure will cost me an arm and a leg!

[atraudes]

I'd take it back and tell them to fix it. It sounds like a direct correlation between the work they did and the symptoms you're seeing. I'm not super familiar with the 05s and up, but I think you use drive-by-wire and the throttle body is overreacting to input.

[Platinum04]

It may need to re-learn the idle code for the computer, dealer issue, sorry