Studdering under heavy load, low RPM's
 

Hey guys, I need some help. Ill start you off with a background story.

Maybe about 3 months ago, my 1997 3.8L with 46,000 miles was having a slight problem. It would happen when my car would be accelerating slowly, around 2 or 3k RPM, and it would slightly studder. It wasn't too noticable unless you were expecting it. Anyway, to me, it seemed like there was a fuel problem, so i ran a fuel system cleaner through it, but it didn't do much. SO i eventually took it to a shop, and they changed the spark plug wires, and it fixed the problem right up.

Anyway, fast forward a month or two, and i install pacesetter headers on my car, and the problem seems to come back. Also, when i stick my head in the engine bay, it sounds like theres a slight sticking. I thought it could be a valve? Im not sure, anyone have suggestions? do you think the heat from the headers fried my wires or plugs and its missing? Also, check engine light was on, came off the next day, and is now back on. Ill have it checked for codes soon.

Thanks

could deff be a melted wire go out at night and start if its arking youll deff know

^ Exactly what I would suggest. If it's arcing enough to hear it, you should see it in the dark.
Another thing, is it possible that you may have accidentally cracked a spark plug during the header install?

I also agree with ^^. If the code you get is P0301-P0306 then it is the plug or wire that has failed or was damaged durring the header install. Each of the #s in the code represent the cylinder that is missing such as P0304 is Cyl 4 missfire, etc

Massey

Hmm, thanks for the advice guys. I went out at night, and I couldn't see any spark or anything. But i think the noise is definitly coming from the passenger side.

Is there any reason it only acts this way in low RPM, and not full throttle?

I had the codes read and they came up PO155....which is an O2 sensor. Now, I took my cat off and replaced it with a cutout, so of course that should throw a code. But that code is not supposed to effect the performance of the engine at all, and just warn you that the cats not working.

I still have the same problem, if it was a cracked spark plug, would I be able to see anything? Would it make that ticking noise?

Thanks

when the engine and exhaust are cool, there is a spray solution to help the spark be more visible.
but you can use regular water or even i bit of soap in a spray bottle to lightly mist the wires and plugs lightly until you see the spark jumping. and it sould make it missfire much more with the wet.
if it's a cracked plug it will go to the block shortess route it can find soo it might be hard to see, if you can hear the snaping noise ... it should really show up on the missfire data as your driving ... should ... lol

I had a friend that had the same tapping noise after he installed his headers. Come to find out that it was the gasket. Exhaust leaks can sound like that.

ok, so even if it is a leak, that still doesnt solve the sputtering problem

could run your hand along the wires till you light up. lol. the ark could be in a spot u cant see. how old are the plugs? may be a good time to get a set of new plugs or get yourself a new spark plug and start switching them.

With having similar experiences with my car, I'm going to agree with the faulty wire or plug ideas. Mine would display a slightly noticable stutter on a hard acceleration, but when you out a load on the engine at slower speeds the motor's problems got noticably worse.

Ok, well heres an update, my car is still studderimg, and I replaced one spark plug on the side i think its coming from, i cant get to the others. the spark plug had a brown ring on the outside of he ceramic part, im not sure what its from? I was thinking an exhaust leak is getting that spark plug hot, and ruining it. Because when i originally replaced it, it seemed to be running fine for a day.

ok ... that's good news though!
sort of ?
do you mean you changed one plug and it ran good for a day?
at least you found the cylinder.
now check the new plug you just put in again.
if it has a brown ring again already. usually that is a sign of leaking threw the plug.
be very careful not to overtighten the plug putting them in or even put pressure on the porcelin while threading if you need to use extensions with universals and hanger bearings to get at it.

ok i had the same problem . i had random misfires . so i changed the coils and the wires and the plugs . . but now the random misfires became a cylinder 6 misfire . so i checked the vacuum lines they were all cracked so i changed them . . . there is no leak . i think . .... but i still hear the misfire . .any other suggestions ??? my maf is good . my throttle sensor might b bad but i thought it im puzzled ... might it be the line connected to the fuel pump ?
oh . when i start my car . the ses light flashes . for like 10 seconds then it just stays on . .