Blah.

[wombat]

Okay so my car has been weird lately. The past couple days, it's been very rarely misfiring slightly, which I figured was no HUGE problem...so today, I'm driving home from work and I figure, hey lets see if it's still doing it. I floored it in 2nd gear, and noticed I had a reading on my interceptor (Don't know how accurate these are) that cyl. 4 was misfiring (typical for our cars). Anyhow, I also saw a KR of 4.3 (I think that's bad?). I wanted to know if you can FEEL knock when it happens, because I didn't feel anything (which leads me to think it's false knock)...Anyhow yeah, what could be wrong? All I can think of is changing the plugs.

cliffs: knock, misfire, change plugs?

god I'm fucking tired.

edit: I want to also note that the car still feels perfectly fine...pulls hard like it should, and feels great (until it misfires)

Click to read more...

 

[bikrboy128]

knock retard is the PCM pulling timing to stop detonation and prevent damage to the engine. so with 4.3* of KR you don't feel the engine knock because the PCM is stopping it by pulling 4.3* of ignition timing.
for every degree of knock about 2HP is lost, so you are loosing about 9HP regardless if it is false or real.


change the plugs (should be easy on your engine), check the fuel pressure, and clean the MAF off just for shits. also check for broken exhaust hangers, loose motor/trans mounts, or really anything that could rattle and make noise that would cause false knock.

i have a whole writeup on knock retard if you want to read up on it.

 

[wombat]

Only reason I was noting the false knock, is because of my trans mounts...(They're aftermarket) I'll clean up the maf, and change the plugs and see what happens.

 

[Dasfinc]

Coulda just been a bad batch of gas too, I'm hearing all kinds of fun rumors about what some companies are doing to make more profit on gas...

 

[WhiteDevil]

id pull the plugs, inspect em real well, make sure they are gapped right.

Then id check the injector pulse on #4

After all of that, id replace the plugs wire cap and rotor.


You will defenitely feel a knock and hear it too.

Mounts wont disguise it.

 

[bikrboy128]

You will defenitely feel a knock and hear it too.

you will feel the knock if the computer cant retard timing enough. with 4.3* the computer has it under control and the driver wont feel it knocking.

 

[MuffHugger]

What mods do you have done?

 

[wombat]

Too many to list. Stg2, 2.9 pulley, header/catback cai. those are the main engine mods. I filled up yesterday, and it seems like it's better...we'll see though

 

[Bob Kazamakis]

id pull the plugs, inspect em real well, make sure they are gapped right.

Then id check the injector pulse on #4

After all of that, id replace the plugs wire cap and rotor.


You will defenitely feel a knock and hear it too.

Mounts wont disguise it.

 

[Lord Tin Foilhat]

sounds like a fluke. check plug gap, clean maf, clean TB, replace your fuel filter/air filter.

chris had the same problem, was seeing misfires at idle, but fine uptop. its probably the tune aswell

 

[wombat]

I put the techron fuel system cleaner in it when I filled up a few days ago, filled it up again today (Yes I burned through that gas basically on purpose), and it feels fine . Still gonna change the fuel filter/plugs tomorrow. oil change too.

 

[wombat]

oh and gas is now 3.99 by my house. first time I've seen it under $4 in a while.

 

[MuffHugger]

3.89 in Downers.