#3 misfire on 2000 SW2

I had a guy at the local AutoZone pull codes on my 2000 v-6 wagon. I've got a couple O2 sensors out and a #3 misfire. I figure I should change the plugs. The problem is I can't even see the plugs. What's involved? I looked at a Hane's manual for the car, but it was no help glad I didn't buy it. Does anyone know where to find instructions online? I'm not willing to pay Saturn $xxx to change the plugs if I don't have to. I know I'm gonna have to buy a bunch of those fancy star shaped sockets, what are those even called? Are there plug wires that can be replaced or does each plug have its own coil?

Oh, and if you've got better suggestions than replacing the plugs let me know. The engine lopes when in idle either with or without being in gear.

Well thanks for your input, Paul

I've got the lw300 (2001) The female Torx bits are sold by lisle This it, I believe

Past that you need a fancy pliers to remove and reinstall the snap rings on the intake plenum tubes. I've been meaning to do the plugs on mine but haven't had a chance to pick up to pliers yet. I've got the Torx set and the fuel line separator tools...

Just a note on damage from an old spark plug. As the plugs wear, the gap increases and the voltage that the ECM sees from the plug firing increases proportionately. Eventually, it puts more strain on the ECM and spark module. Likely that the plugs just need to be changed but could also be the coil over plug module.

A shop manual from Saturn is definitely worth the money if you do an work yourself. I got mine from Saturn parts but you can also order through

Oppie

How many km/miles on these plugs??

We had a 2000 LS2 sedan; had 178,000 km on it when we sold it; the original plugs were still in service when sold. We had several SES "codes" and these were all solved without changing the spark plugs. This V6 has the coils attached to the plugs. Plug replacement is a major task, as the intake plenums need to be removed. Ensuring a good seal on these plenums is diffucult without the special tools.

If you can repair enough to clear the codes without changing the spark plugs, give it a try.

If you are in the 200,000km+ (125,000 mile) range the plugs may need to be replaced. David

The car has 125,000 miles on it. The cylinder is definitely misfiring, you can feel it when idle. Under load (driving) it is not really noticeable. If there could be another cause than a bad plug then I'd like to investigate that..perhaps you could expand on how you expand on how you cleared your SES codes? Thanks, Paul

throughwww.helminc.com

Ah, those are female torx, now I know what to ask for at least. Hopefully the coil(s) will be ok. Hmm special pliers for the snap rings. I was planning on using hose clamps. Someone sells ones that are ~1/4" wide I imagine that should work just fine, right? I do not have the fuel separator line tool however. It appeared to me that it just had a latching mechanism that held it together.

This just started last week we haven't put too many miles on it since. Hopefully the coil is still ok, hopefully.

Thanks Oppie

No problem. The fuel lines need a tool that inserts between the halves and moves the retention spring out of the way. You will never get it apart without the tool. They're cheap plastic tool sets. worth having in your tool box.

Have you ruled out injector or fuel problems? Changed the fuel filter lately? Checked fuel pressure? Run some good injector cleaner through the system for possibly a couple of tank fulls. When idling, the mixture is pretty lean and if the spray pattern is not good from a fouled injector, it will not ignite - missing. How is oil consumption on the engine. All Saturns burn a quantity of oil. Just hope that it is not so much that it causes a miss. Finally check for vacuum leaks by pinching off vacuum hoses and listening to see if the missing stops. Might also read out parameters with a scan tool (not a simple code reader) to see if anything is awry - like fuel trims.

I've never changed the fuel filter. I did add some Chevron injector cleaner at 4x strength, didn't seem to help. I could add more, but don't have much faith in it. I can check for vacuum leaks, cracked hoses etc., easy enough. Though I doubt a vacuum leak would cause only #3 to misfire. It is misfiring at a very regular rate, if that tells you anything.

I just changed the oil, hell I bet that's it. I put in 5w30 and had been using 10w30. I bet its pulling in more oil and fowled the plug, damn. I probably still should change the plugs though with 125,000 mi on them.

Thanks your replies are greatly appreciated, Paul

There could be a vacuum leak on one of the plenum boots:

Also, the Saturns are well known for the exhaust valves sticking open a bit at that mileage.

The reason being that:

1- They ream the valve guides just under 8MM/5-16" at the factory, to help prevent oil leaking down the stem. (Seals were optional, depending on valve stem tolerance)

2- The little oil that does go down the stem cokes on the stem, and at certain RPM ranges, the valve hangs off of the seat slightly.

That's where a leak down test, or even better; a running compression test comes in. But not applicable on this engine except for the leak down test.

I would suggest you remove the plenum, a do it yourselfer grade of cable type hose clamp pliers, are available at Auto Zone for about $20.00. (They really come in handy)

Do the plugs, valve cover gaskets, and at the very least, do a compression test.

I h>>

Changing the fuel filter is cheap insurance. A bit of crud that gets into the injectors is expensive to fix. You'll notice a lack of power or hesitation on acceleration due to flow restriction from a dirty fuel filter. Shouldn't affect idle much though.

A single cylinder misfire due to a vacuum leak sometimes happens from a leak in the intake manifold near that cylinder. The tried and true diagnostic method is to do a visual first - then use a propane torch (flame off and just as a gas source) and go over all the joints. The gas will get sucked into any leaking joint and you will hear a change in the rpm or misfire. Propane is heavier than air so will sink - in still air.

Can also use a stethescope to listen for sucking sounds.

Hey RK, What do you mean by "a do it yourselfer grade of cable type hose clamp pliers, are available at Auto Zone for about $20.00. (They really come in handy) "? Are these pliers to remove the snapped-on type hose clamps?

Thanks for the info, Paul

PS I may need info on removing oxidation on my '68 Mustang after I'm done with this don't go away, just yet!

Hey Oppie, Thanks for the tips on checking for vacuum leaks, I've never heard of using propane, cool. I've also got a stethoscope, maybe I'll use both. I've already got my f-torx bit set. I found them locally for $30 hopefully I'll get to use them before they come out with a different style.

I saw a plastic set of AC Fuel line removal tools at a parts store, but couldn't figure out how they applied to the (braided metal) fuel lines on my 6cyl. I remember needing something similar when I replaced the fuel filter on my '94 Saturn. I'll need to look at it again and get a better feel for what I need.

Again much thanks, Paul

On the L300's I worked on:

The clamps were like the spring type clamps.

With a flat >> There could be a vacuum leak on one of the plenum boots:

My son rebuilt a '68 mustang over the last couple of years. He got the car by way of ebay motors and had it shipped from Los Angeles to here in NY. Not a numbers match so just a fun car.

Gutted it Crate engine from Bill Mitchell. Nitrous kit (not tried yet). MSD electronic ignition. New 5speed transmission (the one used in new 'stangs) Had to re-size drive shaft. Replace dashboard with a new electronic one. Gauges all look original but are electronically driven from a module. Uses all new transducers and sensors. Air ride suspension with automatic ride controller. Rack and pinion steering conversion. Racing suspension front and rear. Roll cage and 5 point harnesses. custom stainless steel headers and exhaust system.

The engine was contracted to be a fairly base model. When he drove out to pick it up, he was offered a *much* more exotic engine that a racing team lost their deposit on - for the same money (about 8G) For quite some time, we had almost daily deliveries from Mustangs Unlimited and other suppliers.

He did an impressive job on it. I am still having trouble reconciling that he spent as much on the custom exhaust as I spent on my used Saturn LW300... He just got married and bought a house. Most likely anything new on the car will wait a while.

My '68 is a daily driver, I've had a child's seat in the back since I brought it home. Drive it to/from work every day and drop the kids off at school/daycare. I work on it to keep it going. It's got a big Holley 4bbl on a 289 and a Holley intake/exhaust. My latest work on it was doing a Shelby mod on the upper A arms when replacing the springs and ball joints. I've installed racing seats. I wish I had the $$ to do what your son did on his but wife, kids, mortgage.. he'll see soon enough. Have your son check out National Parts Depot (NPD) he can download their catalog at

. Their prices,parts, stock and service, imo, are superior to Mustangs Unlimited. Last night I looked things over and it doesn't look like I'll even have to touch the fuel lines to get to the plugs [If the plugs are beneath the ignition packs(?)]. I would need the tool to remove the fuel lines for sure. I removed the battery cable on the car to reset the codes. Upon restarting. the car ran fine at idle, bring it up to

1000rpm and it was rough past 1200 and it was fine. Drove it a little and it seemed fine. Started it and it ran like crap again. I don't know if that tells you anything, but I thought it was interesting that without the "computer" having any saved information about the car it ran much better. Still planning on replacing the plugs, filter and boots(if the boots are replaceable).

Later, Paul

Plugs are under the ignition packs but there is a lot that has to be removed to get to them.

Simple way on the L series to reset the codes is to pull out the 'Controls B+' fuse for 20 seconds. This resets the ECU but doesn't loose your radio presets...

Past that, I couldn't hazard a guess on what's wrong. when in doubt, take it to a good independant mechanic for a diagnosis.

Thanks for the NDP link, I'll pass it on. (at this point, he's got $70G into the car.)

Oppie