ok so here it is...my egr cel was comin on for a while so i figured i would try to fix it...long story short i ended up replacing the valve, pulling the manifold and gave everything a very thourough cleaning. replaced old gaskets with new ones and i thought that was it. start up the car and it seems to be running nicely, even idling smoother. COOL. take it out for a test drive through the neighborhoods, main roads, and then take it up to bout 95 on the high way ***** to the wall. no cel came on. start it up today and after 5 mins. of easy driving the cel light comes on. its registering code 1400-egr and another code saying something to do with my knock sensor.im wondering wat is going on since before this my knock sensor light wasnt on and now it is. i didnt even get close to messin with the knock sensor while i was under the hood. can anyone please help me with this mystery? and also after replaceing the egr and cleaning the whole system why is it still throwing the code?

 

your knock sensor may have tripped cause of an O2 sensor. It tends to do that. Maybe the new valve was faulty giving you the code again. The KS could hav tripped due to the going "***** to the wall" and doing something to the O2 sensor. Ever replace the O2 before?

I'm not a mechanic, but from reading the org 7.5 hours out of my work day, this is a fairly common problem with the KS Code

 

see the thing is though that before the knock sensor never came on. ever. and yes the o2 synsors should be in good working order. no codes being thrown for them. im still at a loss for words.

 

but the KS is known for being ghost. And when something, anything happends to an O2 sensor it sometimes sets off the KS.
Sometimes the KS code isn't thrown even when it is bad.

You can get them for 50 bucks on Ebay. I actually ordered one teday.

 

ok.....if i was to replace the o2 synsor in light of this baffeling knock synsor, how will i know which 02 synsor to replace since there are none that are registering on the obd2? i mean that sounds like a plausible fix, i just dont wana start replacing part after part to try to take care of something that im not even sure will be fixed by replacing these other parts. im not too sure how the whole knock synsor thing works, but would something like replacing just the knock synsor solve the problem? im really open to any and all ideas at this point.

 

this is just what i've been reading. And there are alot of credible people on this site that know their stuff. However, in light of this, I had the code come up as well. So I just replaced my KS. OR rather am going to when it arrives. If the code comes back again, I can only assume it wasn't it. But since the KS is cheaper than an O2 sensor and that is when the code is telling you, get it fixed. You will also feel a loss in performance and major loss in gas milage if it is indeed your KS. Right now, I am experiencing both.

 

I think you guys have that mixed up a bit.

The KS code usually comes along with an O2 code.
The OP doesn't have any O2 codes, only EGR codes.

I would troubleshoot the EGR system again. Did you clean the EGR pipe in back of the intake manifold? Was the valve working correctly?

Get the EGR issue fixed, then see if the KS code keeps coming back. You will have to check for the code as if it is the only code stored it will not set a CEL light.

 

yes the egr pipe was cleaned and the valve is new and in working order. i really dont know where to go with this one. i think i might have to break down and take it to a mechanic to do the rest. i just dont know... what would you reccomend.?