Rough runnin'

[Colin]

My car started acting up Monday. I started it up to a really rough idle, and when I accelerate, it's really rough. There's a noticeable loss in horsepower, and when I do mash the gas, there's hesitation and roughness. Bascially, it's just not runnin' smoothly like it did. All fluids and gauges are fine. I'm thinkin' misfire, but I wanted to get some other input. Plug coils are all intact and in good shape too.

[North Cali Autocrosser]

Any codes showing? When was your last tune-up? Check for vacuum leaks, with these symptoms it would probably be a major one. Also check for burnt wires and measure the resistance in them.

[Colin]

No codes, and my last tune up was a few years ago. It smoothes (sp?) out quite a bit after it's been running for a while. I thought maybe it was just bad gas (can't get nothin' decent for $3/gallon anymore) so I ran some Chevron w/Techron through it a couple of days ago. This kinda' thing has happened before, and it was my tranny filter, but the roughness was only at high speeds, this is all the time. There's almost a rhythmic "lope" to it, which is why I thought it might be the plugs.

[North Cali Autocrosser]

I've never had a plug just quite they usally go away over time, but I have had wires just crap out. I once had a PCV valve that grenaded on me and it caused the vehicle to buck like crazy through out the rpms and while cruising.

[Colin]

Well, I kinda' considered the PCV valve. Aren't they pretty expensive, or is the O2 sensor expensive? I remember researching one of the two, and one of 'em was pretty pricey. This rumble has happened before - when I first start the car in the mornings, it would idle kinda' erratically (sp?), but I'd drive it a couple of blocks and it'd go away completely, and this wasn't even an every day thing like it is now.

[North Cali Autocrosser]

PCV valve is only $3-4 and an O2 is only $25-30. I also forgot that the PCV that blew up on me was on a carburated vehicle so a huge vacuum loss could effect it more than a fuel injected but I'm not exactly sure.

[Colin]

Yeah, I'm thinkin' it's a plug (or plugs) so I'll probably pull them out either Monday or next weekend. Have you ever done a plug change on your 3.1?

[North Cali Autocrosser]

Yeah, you'll want to do it when the engine is cool the EGR side sucks when it's not. Most are easy to get to but there is one that you will curse at. I used to have a bad problem with plugs, I'd go through them about every other oil change but once I put a new set of wires on them and switched to NGK plugs I haven't had anymore problems.

[96RS Alex]

Now is the time to Seafoam your car.
I've done this before my last plug & oil changes and it runs a hell of a lot smoother now.
3.1 plug changes are fairly easy, just take your time and check & replace that rotor and cap assemblies if youre going all the way.

[Colin]

What I was wondering is there is one plug that sits kinda' behind the alternator and it looks like it's going to be a beyach. Another thing is my plugs seem to have a metal "sheath" kinda' thing on them. Does that come out too? There's a wire with a disc-shaped cover on them. I tried pulling them out, but didn't wanna' force 'em until I was ready to replace it all.

[96RS Alex]

The #2 spark plug that sits behind the alternator can be easily removed by taking out the alternator assembly first.
Detach by loosening the serpentine belts tension to remove the belt off the pulley and then remove the alternator. You should have enough room to view & remove the #2 plug.
The metal sheath is to protect the boot & sometimes they have a paper lining inside it that also protects the plug boot as well. Push the metal sheath in as far it can go so you can pull the rubber boots out from the plug. Not sure if your sheath will have the paper linings as I dont have the part number for that yet. Don't forget to install a dab of dielectric lithium grease inside the new spark plug boots, ask your auto parts dealer to check if the new plugwire sets already has them greased, if not they have some behind the counter for sure.
I'm quite not sure yet what that wire/disc combo youre talking about but please disconnect the battery terminals first before you start removing parts.

[Colin]

I got to thinkin'. . .could this be an exhaust or driveshaft problem? It'll periodically go away almost completely, so I'm kinda' thinkin' it's the wire(s), but I'm going to replace all plugs and wires this weekend hopefully. I ask if it's an exhaust problem 'cuz you can smell exhaust in the car when it's first started and I can hear a "ticking" (almost like a small backfire) from the back passenger side of the car (I have a single in - dual out muffler). The driveshaft issue is 'cuz it vibrates HORRIBLY when accelerating in lower RPMs, though I tend to rule out the driveshaft 'cuz it vibrates even at idle.