Plugs and chugs and oil leaks

[gorckat]

94 LE 5SFE ~240k miles

Did my plugs, wires, cap and rotor this past weekend. Ran smoother than previous. I was happy.

Yesterday I hit the grocery store on my lunch break and when I started the car up ~10 minutes later it was idling real low (~500 RPMs). A/C and everything was off. Giving it some gas didn't make it open up (like it would before I replaced the intake and cleaned the throttle body), but once I was driving it was fine (~5 minutes back to the office). Ate my salad in the car with it idling, no issues.

This morning, it sort of missed (I think) or maybe it was a lope when I started it up- it started up but chugged briefly (rough idle, RPMs dipped momentarily and then went back to normal). Did it a minute later as I was coasting at about ~15 MPH, and I decided if it did it again before I was halfway to work (10 miles, 25-30 minute drive) I'd turn back and check the car out. It did a couple minutes later, so I came home.

I let the engine cool and a little bit ago just got done checking the gap on all the plugs- #4 was ~.050 so I closed it to spec; the other three were spot on. The same tube's valve cover nut was finger loose (missed that Sunday) so I checked the tube seal and it was all crispy. All four will be swapped tonight after looking at them.

Questions:

1) Would the gap being off like that cause a miss/lope intermittently?
2) Could it have caused the low idle yesterday?
3) Since I have all four valve cover nuts off, should I go ahead and replace the valve cover gasket? I didn't think this through and was looking to save a minute later, but by popping the three tight nuts off, did I compromise the gasket? I think I have a small leak or two around it anway- no noticeable drops in oil level, but looks like some long-term leakage residue on the back near the #4 plug, and on the #1 side near the distributor.
4) The #1 plug had oil on the threads the other day and a little more today- what am I looking at to solve that? This valve cover nut was the loosest of the three that I had to use channel locks on, so could it have been just the tube seal? I did see a little oil in the tube when I checked with a flashlight.

[hill8570]

Mis-gapped plug can certainly cause a miss or lope.

Plug problem unlikely to cause the low idle. Sticky IAC valve more likely.

Unless you gave the valve cover a good wack, I doubt you compromised the gasket -- those suckers are stuck on pretty good after a few years. Replace it if you want, but it's certainly not critical right now.

If the oil is also on the ceramic part of the plug, it's usually just the tube seal, especially if you're not blowing blue smoke out the exhaust.

[gorckat]

Okay, so I put things back together. Couldn't find a 30mm socket at the part shops, so I tightened the nuts trying not to overdo it. I hope it was tight enough. Gave the IAC a little squirt of Deep Creep.

A test drive showed no stumbling or anything last night, got to work okay.

On the way home today it seemed like it was a little funky, so I tried to observe if it was more noticeable after heavy braking or harder acceleration. Every couple minutes prior (on that 25 minute drive to my daughter's daycar) between stops while idling, the RPMs would be sitting pretty at 750, then chug ever so slightly and the needle would drop maybe a little more than its width and it would pick right back up ok.

No dice finding a cause. Then...

Got to a stop light, cut off the a/c and fan just to hear things better. Gave it moderate acceleration and it stumbled a bit, a little herky and jerky and it got to 35 okay. Half mile later, another light, same thing but not as bad. Got to my daughter's daycare a couple miles later and it stumbled as I shut it off.

Got home (two miles) with it getting a little rougher at idle (tried to roll through the stop signs where possible). Stalled as I pulled in front of the house.

Let it sit a second and tried to restart so I could try to pop the hood and maybe see/hear something. No go- sunded awful turning over, really rough. Let it sit a little longer and tried again, giving a little gas to make it go. Nothing.

Got out, cursed, smelled lovely burny smell. Kind of like rubber. Popped the hood and wisps of whitish smoke were coming out of my air filter.

W.T.F? (No hits for a problem like this searching "smoke air intake")

Did I not crank the plug nuts tight enough and I blew something?

[gorckat]

Alright- just changed out of the monkey suit :P

Coolant level looks ok. Oil level is good and looks ok (only a couple weeks old), plug nuts look good (no signs of oil around them, at least). Plug and cap wires tight. Had a devil of a time getting the oil cap off, but I assume that is due to expansion since the engine is hot. The cap does have some old sludgy gunk in it, but its been there awhile (another reason I'd rather not pull the valve cover if possible!)

Made a visual inspection all around. Saw some fluid to the left of the oil filter, but it's still to hot for me to stick my hand in there and see what/how old. Unfortunately, long years of lack of engine cleaning have an accumulation of oil and gunk all over the place. I did not see anyplace above the fluid that looks like it was leaking (it was sitting on a horizantal spot on the block, I think, and not at a seal of any sort that I saw).

Tried to start it up again. It turns over but gets no go. Fuel filter? Ignition coils?

[gorckat]

After talking to my father-in-law, he thinks I should give the distributor a once-over this weekend, so I was looking at it in my Haynes book.

Any other ideas?

[JohnGD]

When you start to have problem after changing parts, then I'd first suspect those parts, after checking for disconnected hoses/wires in the process.

If you happen to have kept the old parts, maybe try swapping the wires and cap/rotor back first and see how things go.

What plugs (and wires, cap, rotor) did you use? I always like to spec NGK Iridium IX (or Laser-Iridium) for these. If you need to save money, the NGK G-Power platinum is another good choice. You shouldn't need any other plug besides these two. (NGK wires are good choice too.)

Originally Posted by gorckat

94 LE 5SFE ~240k miles
Did my plugs, wires, cap and rotor this past weekend. Ran smoother than previous. I was happy.

[JohnGD]

You might also want to check the vacuum reading on the engine. Plug/tee a Mityvac into the EVAC port and see if you get 17-22 in/Hg.

Check your local parts store, such as Autozone, for free loaner tool program.

[hill8570]

Originally Posted by gorckat

Tried to start it up again. It turns over but gets no go. Fuel filter? Ignition coils?

Well, following the principle of "the last thing you touched broke it", I'd suspect that the IAC really got annoyed with the Deep Creep. Did you spray it inside the throttle body, or on the IAC outside the TB?

Another possibility is the coolant temperature sensor (a bad one can cause serious idle and starting problems).

Check for spark, too (pull one of the plugs and see if you're getting a nice juicy spark when you crank).

Smell the plugs -- are they "gassy" smelling? If no, spray 5 seconds or so of starting fluid into the air intake, and see if she tries to catch.

[gorckat]

Looks like it was a defective part. Before this morning, I'd only had a couple 15 minutes looks at it- double checking plugs and connections, cleaning battery terminals again, stuff like that. Didn't get it started.

This morning I looked at the old wires, plugs, cap and rotor. I popped the new cap off and was checking the connection when I recalled an obvious piece of important info- the old rotor was on the distributor shaft very tight. I had to use a flathead to gently pry it off enough for me to get a good grip on it and remove it. The new one had a little bit of play.

I used a socket to double check the fitment between the two- the old one was clearly tighter fitting. I cleaned it up a little and popped it back in and she fired right up. Took the defective one back, swapped it out checking its fitment with the socket at the counter. I haven't put it in yet (had to get the wife's oil change done first) but I think that was the problem.

If the rotor was "wobbling" on the distributor shaft, does it make sense that it could fire early or late causing the misses and stumbling? Or is something else more sneakily intermittent lurking somewhere?

[hill8570]

Originally Posted by gorckat

If the rotor was "wobbling" on the distributor shaft, does it make sense that it could fire early or late causing the misses and stumbling? Or is something else more sneakily intermittent lurking somewhere?

Good catch. Yeah, it makes perfect sense that a wobbling / poorly connected rotor could cause firing problems. One of the many reasons I'll pay the extra $$$ for OEM parts if at all possible.