Hi. Alright I did a search but could not find the answer to my specific question. Thanks for helping.

I had 2 sensors go off, 02 and Knock. I changed the 02 and reset ECU with Snap-On Diag tool. I drove for a week and MIL came on. Found out that Knock sensor was back. Tried to reset it and the MIL went off but the knock sensor error remained. Tried 5 or 6 times, cannot reset it. Car runs fine, sluggish because of ecu but fine. I fill up 92 and see no visible problems. Should I buy another one or is it something I am missing or should check?

Thanks again,
Erik

 

you won't really notice it, i never noticed how bad mine was, but it's the only reason i can think of why my 95 was so slow, it threw that code and i never changed it. medicsonic changed his and said BIG DIFFERENCE.

 

There is a difference. I ran the track with o2 and knock and I ran a 16.5...with the o2 off I ran a 15.5...so without the knock I suspect it will run even quicker...the sensors will slow you down.

Erik

 

when i said you won't notice it i meant you won't notice how bad it is. but once you change it it will be much better.

 

If I suspect one of my O2 sensors giving the wrong reading, but have no check engine light... what should I do other than testing them, because I've tried to test them and I just can't seem to figure it out.

I figure that if I disconnect all three of them, it will cause the car to run open-loop (ignoring the O2 sensors misinformation). And therefor if my car runs better with the O2 sensors disconnected then I know that is my problem. I know the car runs open loop until it reaches normal operating temperature, then switches to closed loop... it's right about the time that it would be switching the loop (and fuel mapping) that my car starts to hesitate when accelerating. So I figure if it runs good in open-loop, it should still run OK if I make it run open loop even once it's reached operating temperature by disconnecting the O2s. If it runs OK after I do that, then I know my culprit is the O2s... if it still hesitates I know it's something else, like maybe the coil packs?

Does this sound right to any of y'all or should I rethink my plan of action here.

Thanks!

 

rethink.

 

yeah, definitely rethink. Did you pull the codes the second time the CEL came on? The knock sensor doesn't trip the CEL so maybe something else is bad, or maybe you checked the wrong O2 sensor? I know our cars have at least two O2 sensors, I think there are really three, but definitely two. Your car will run its best when all the sensors are properly working. Good luck.

 

Im not sure if your talking to me, but the knock sensor set off my MIL or CEL...the Snap-On Diag which is 100% accurate reported it as the only malfunction.

Erik

 

if you knock sensor makes the CEL TURN ON then iot's gotta be far gone. get a new one.

 

OK could you be a little more specific? What should I do?

I have a slight hesitation/loss of power/hiccup during acceleration only once the car reaches normal operating temperature. 10k-15k miles ago the check engine light was on and the shop I took it to said "knock sensor code and air temp sensor code"... and that's all the info I got from them. The light disappeared soon after, but I'm stuck with the hesitation and it's driving me nuts. I have a brand new fuel filter, PCV valve, NGK plugs, cleaned throttle body/butterfly valve, brand new airfilter, fresh synthetic 5w 30 mobil 1 oil and filter, about 5 cans of fuel system cleaner ran through over the last 10k miles, and only use Amoco 93 octane gas. What am I missing here??