I am really getting discouraged. Let me start by saying I had a 97 Max 5-speed w/ 146k on the odo. Replaced the spark plugs around 120k and one of the engine coil packs at the same time, so I def know what it feels like when one of those go. Also, I believe the person who had the car before me stated he had the KS and O2 sensors replaced right around 100k. Do these things fail more often than once? Esp w/in 3 or so years?

So my symptoms:

Let me start by saying a few weeks ago I filled up at the gas station and it was within 10 miles that the symptoms started to occur. (I was below 1/4 of a tank when I filled). The car started having serious acceleration issues. It would jerk and sputter and just all around horrible when I would try to give it any sort of modest gas. The only thing that would prevent this was driving like a great-grandmother. It was especially bad in 1st thru 3rd gears. Hasn't thrown any codes yet... Got it down to half a tank of gas, put injector cleaner in it and filled with super. I've driven 20 miles so far and it hasn't seem to go away. I was reading about KS symptoms and they seem really similar but the last thing I want to do is shell out 100+ bucks for that thing esp if I am not sure that is it.

Here is the kicker though that is making me (hopefully) think it is otherwise: My dad filled up his car at the same place the same day, and started getting some serious acceleration issues too. After driving a lot and a fresh tank of gas, his car is fine now. I haven't put as many miles on mine as him yet but I did put the injector cleaner in and a new tank o gas. Do you guys think it is likely that it was bad gas and it's just going to take longer to get outta the system? We are going to change the fuel filter this weekend sometime too just b/c I think it is overdue and the part was like 8 bucks at the auto parts store.

Sorry for such a long post, just wanted to try and be as detailed as possible to narrow it down. What are people thinking, KS, bad gas, just keep driving it?? Thanks

 

You and your father both experienced the same symptoms on the same day after purchasing the same gas from the same station. Drive it, maybe get some drygas, although most injector cleaners already contain it. And the fuel filter change definitely wont hurt anything.

 

Also as a side note because from what I gathered another side effect was poor gas mileage, but I put 9 gallons in after driving 200 miles, so that was right about in line for normal gas mileage..

 

Use aviation fuel if u have a sunnco or other gas stations like this its way better then any other fuel additive imo.

 

hey im havin the same problems!!! its not your gas it is your knock sensor
although not CEL go to advanced and read codes. itll say your knock sensro
got my new, its goin on tomorrow. hope it fixes it, if not im gonna be one PISSED OFF ****, for sure!!!!!!

 

So his dads knock sensor went bad at the same time? I drove with my knock sensor unhooked and had no problems other than retarded ignition resulting in poor low end torque. (unhooked it as an alternative way to test if it was bad)

 

Well he didn't replace his knock sensor and it went away. Hopefully it was just the bad gas, but I thought filling up with fresh gas would have made it go away. When you say lack of low-end torque caused by a bad knock sensor, do you mean it just feels like a weak engine or do you get the violent jerks as you increase speed. Let me know how your knock sensor replacement goes. I am praying on just running it more and it going away over the weekend.

 

No bucking or jerking whatsoever and my knock sensor was laying on the passengers seat. I checked for the code only because of extensive reading on here and the fact that my car felt sluggish under 3k rpm. Try to find gas without ethanol.

 

its been bad!! dont matter where i get gas!! its gettin changed in 2 hours!!

 

check the sensor with a ohm meter. the resitance should be around 550 k ohms. you can check it at the harness vs taking it out and testing it

 

A faulty (or missing) Knock Sensor will NOT make the max jerk and sputter, or anything remotely like that. All a knock sensor does here is enable the ECU to advancing the timing as much as possible given the fuel and conditions, to give you slightly better torque and fuel economy.

 

A bad knock sensor WILL definatly give you jerking/sputtering...

 

I drove 2000 miles with mine bad and 150 miles with it unhooked and laying on the passenger seat. Never jerked or sputtered once, was just a complete dog under 3k.

 

I could be wrong but I've heard that the knock sensor is triggered when gas with too low an octane rating (lower firing temp) is used causing the spark plug (and cylinder) to fire prematurely, (pre-ignition) due to the high pressure, thus throwing off the engine timing (and hence the knocking). The knock sensor senses this and adjusts the firing accordingly... Am I off?

 

no your pretty on. a knock sensor is like a microphone to hear for a knock and retards timing if a knock exists

 

yeah like ZX9RBART my 98 max threw up knock sensor code quite some time ago but no sputtering or jerking... Ive yet to replace it