# ~~~\> Please Help NOx Problem **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [September 30, 2018, 4:31am UTC](https://community.cartalk.com/t/please-help-nox-problem/125922 "2018-09-30T04:31:09Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![silence820\_142747](https://avatars.discourse-cdn.com/v4/letter/s/3d9bf3/32.png) [@silence820\_142747](https://community.cartalk.com/u/silence820_142747)\ **Post date:** [September 30, 2018, 4:31am UTC](https://community.cartalk.com/t/please-help-nox-problem/125922/1 "2018-09-30T04:31:09Z")
I really need some advice. I have a 2005 chevy tracker. It came from the factory with a 2.0 suzuki engine. It has failed emission 3 times for NOx. 6 months ago, had the top of motor rebuilt. Coolant is good, fan is running, car does not over heat. 1 time fail, changed the Cat Converter. I don’t remember the data for NOx 2 time fail, changed the EGR Valve. NOx 1000+ (when I picked the car up the check engine light was on for the 1st time, then the mechanic cleared the code that caused the light. He said it was because of the change of the EGR valve.) 3 time fail, don’t know what else to do. NOx 800+ Any advice you can give will be appreciated. ---
**Author:** ![pleasedodgevan2](https://avatars.discourse-cdn.com/v4/letter/p/ad7895/32.png) [@pleasedodgevan2](https://community.cartalk.com/u/pleasedodgevan2)\ **Post date:** [September 30, 2018, 4:47am UTC](https://community.cartalk.com/t/please-help-nox-problem/125922/2 "2018-09-30T04:47:46Z")
Other than the obvious EGR system problem there could be an intake manifold leak which could cause too much oxygen to get into the combustion chamber. Then there could be a leak at the EGR valve or near the EGR valve. Something is preventing the exhaust gases from entering the combustion chamber. The knock sensor could be malfunctioning and over advanced ignition timing may be contributing to the problem. ---
**Author:** ![It\_s-Me](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/it_s-me/32/12660_2.png) [@It\_s-Me](https://community.cartalk.com/u/It_s-Me)\ **Post date:** [September 30, 2018, 6:00am UTC](https://community.cartalk.com/t/please-help-nox-problem/125922/3 "2018-09-30T06:00:27Z")
> [@silence820\_142747](#): > > 6 months ago, had the top of motor rebuilt Was it because of this problem? I’m thinking you might have an intake manifold leak. > [@silence820\_142747](#): > > the mechanic cleared the code Would be nice to know what the code was. ---
**Author:** ![Barkydog](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/barkydog/32/2470_2.png) [@Barkydog](https://community.cartalk.com/u/Barkydog)\ **Post date:** [September 30, 2018, 5:46pm UTC](https://community.cartalk.com/t/please-help-nox-problem/125922/4 "2018-09-30T17:46:24Z")
Is your car well warmed up before the test? ---
**Author:** ![silence820\_142747](https://avatars.discourse-cdn.com/v4/letter/s/3d9bf3/32.png) [@silence820\_142747](https://community.cartalk.com/u/silence820_142747)\ **Post date:** [October 6, 2018, 7:04am UTC](https://community.cartalk.com/t/please-help-nox-problem/125922/5 "2018-10-06T07:04:19Z")
the code was for the MAF. i disconnected it while running and the idle got a little better and the car did not stall. i ordered another one and it will be here on the 12th. any thoughts? ---
**Author:** ![It\_s-Me](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/it_s-me/32/12660_2.png) [@It\_s-Me](https://community.cartalk.com/u/It_s-Me)\ **Post date:** [October 6, 2018, 12:36pm UTC](https://community.cartalk.com/t/please-help-nox-problem/125922/6 "2018-10-06T12:36:42Z")
> [@silence820\_142747](#): > > the code was for the MAF No it wasn’t, the code said the MAF sensor detected a problem, not that the MAF sensor was bad. What was the code?