new B needs help please

[LeoSS]

I need some help guys, please!

1999 Nissan Maxima SE 115,000 miles

First off, I am getting a CEL. Codes:P0400 - EGR valve malfunctionP0325 - Knock Sensor Circuit 1 Malfunction (this code was in there 2 times)

recently replaced (with genuine nissan parts) rear o2 sensorEGR valveIACV

First, the car's idle is very inconsistant. When the car is first turned on, everything is fine. Idle around 600rpm, drives really smooth. But after the 2nd or 3rd red light, I start to get a stumble or a hop on the car. This only happens when the car is at a complete stop and in Drive. Idle remains the same, 600 or so rpm. Then after I come off the highway, the Idle climbs drastically. I am at a complete stop and the idle is around 1300rpm (in drive) and feels like it wants to take off. If you let go of the brake, it jumps forward, almost like the throttle is stuck. If I put the car in neutral or park the idle jumps up to 2000-2500rpm. I then put the car in Park and shut her off, wait a minute and turn her back on and she runs fine for a few minutes, and the the car gets a stumble or something like that again, and the process repeats itself.

I am at a complete loss on this. I have cleaned the TB and MAF, as well as replaced the parts listed above, and nothing. Thanks for the help guys.Leo

[AZhitman]

Sounds to me like IACV adjustment is off, went through this with my Q45 recently.

If you don't have a Consult, might be tough to adjust acurately... Maybe one of the Maxima experts can look in FSM and give you some more insight on this.

Welcome aboard Leo!

[LeoSS]

thanks.

I was having these same problems before everything was replaced. I had an o2 sensor code, an egr code, and the ks code and the idle problem for the last month or so. So today I purchased the egr valve, o2 sensor, and the IACV and replaced them, hoping it would fix the issue. We did "adjust" the IACV with a scanner hooked up to get the idle where it should be. Had it set around 600rpm (take 50 up or down) and it seemed to be perfect. Drove like when new. Go down the road, 10 minutes later and BAM, idle problems, a stumble or pop/hop in the car when at a stop. Drive home (about 100 miles) and get a CEL again (codes posted above).