What Happened:
I was driving to school this morning and my car was running as good as it always has, no new squeaks or rattles or knocks. About halfway up one of the hills that my car has to downshift on in order to get up, my car suddenly begins running differently, loses some power, and starts to vibrate. I checked my oil pressure and water temperature (both were in their usual places) and limped up to the top of the hill where I could pull over. Once i got stopped it seemed to me that I now had a dead miss. When I give it gas it stumbles some and doesn't gain RPM's as quick as usual and the sound of the exhaust is different (like a miss). I drove the car back home with it running like crap and all the engine vitals stayed where they usually do. Also, my Mom tailed me home and said that my exhaust smelled strongly of gas.

Possible Clue:
About two months ago my car began running 5-10 degrees hotter (195-200) than it ever had before (190).

Our Diagnosis:
Me and my Dad talked it over and to us it doesn't make any sense to suddenly lose a spark plug and/or wire. The set that's on the car is fairly new but we will still explore that route. Since the exhaust smells like gas we think that would rule out a bad injector. He seemed to think that a blown head-gasket is a possibility. Any other idea's from from the V6 braintrust?

Thanks in advance for reading all of this.

 

Anyone?

 

pull the plugs and check them check the plug wires for arc marks as well

 

Thanks that's one of the first things on the to do list. My Dad tried isolating the miss tonight by pulling plug wires but he had to quit due to it getting dark before he had found anything.
Unfortunately, I'll be at school all week and won't get a chance to any diagnostic work myself until Friday evening and once I'm home I won't have internet access which is why I'm trying to get ideas on other things to check in the meantime.

On a side note. How is it that the spark plugs seem to be self tightening? When my Dad pulled a plug today he had to use a cheater bar to get it out and I know the plugs weren't in that tight. I'm the one that put them in and I used anti-seize when I did because when I changed the plugs they were extremely hard to get out.

 

Same thing had happened to me twice. Once because of misplaced spark plug wires. And again because one of the spark plug wires was hanging and was burnt up. But neither of those times did i have a strong exhaust smell...
Hope i helped a little bit lol

 

I have had one of my plug wires get burned on the exhaust manifold in the past so that's one place I looked but none of them were touching this time. For me, when that happened I only had a miss under load though. Thanks

 

I'd replace the plugs. Seeing as how you put anti-seize on them, one of them could be shorted (gap bridged). NEVER put anything on the plugs (other than dielectric grease on the insulator shells) when installing them. This is probably why they were so hard to get out as well.

 

Maybe I'm just stupid but anti-seize and hard to get out don't seem to go together. Besides the plugs have been in the car for going on three years now so I doubt one would short all of the sudden. I'm not ruling out a bad plug I just haven't had time to check and won't until Friday.

 

Please tell me you understand that the spark plugs are exposed to temps exceeding a couple thousand degrees (the burning of the fuel and air is quite hot if the exhaust alone reaches between 400 and 800*). Things chemically change at those temps. What was a lubricant can become like a glue...

 

Really?!? Who would have thought that compressing an air/gas mixture and then igniting it would result in high temperatures? Besides the plugs were hard to get out before and I doubt the previous owner would have put anti-seize on the plugs.
On another note, the anti-seize I used is Loctite High Purity N-7000 which is temperature resistant to 2400*.
Here's a link if you'd like to see for yourself. I know you'll point out how expensive the stuff is, I got it from my Uncle who found it in a lot of government surplus.

 

You forgot to figure in the gasoline and pressure there, bub... Trust me, these plugs don't need any help getting stuck. Also try chasing the holes with a plug thread chaser and get that crud out of there.

 

I'll continue using my anti-seize and you can continue convincing yourself that it's turning into glue in my spark plug threads. It's had no ill effect on any of the other 4 vehicles we've used it on. If you ever need any and we happen to run into each other I'll give you some for your spark plugs. I'm sure we have some to spare.
This thread wasn't intended to be a debate about the operating temperature/pressure of the threads of a spark plug. If you have any constructive advice that might help me more quickly determine what's amiss with my car feel free to give it. Like I've said I'm going to check the plugs because, not surprisingly, that is a likely source for a miss.

 

Well, are we sure it's a misfire on a cylinder, and not a bad fuel pump? How's the ignition timing, coil, module, and cap/rotor (did the rotor button melt off? Happened to me using a stock cap & MSD)? Catalytic convertor clogged at all? EGR valve stuck open?

 

No, I haven't ruled out out fuel issues at all. We thought it was the cap. I have some pictures I'll be uploading later and you'll see why we thought that. Every time we pulled a plug wire the "miss" got noticeably worse. So I'm beginning to lean toward some kind of fuel issue now.
As for the cat, what cat? It's long gone. Theres actually a muffler resting in it's place due to all the issues we had when we replaced the fuel tank after I got the car. How would I go about checking the EGR valve?
Thanks for the suggestions.

Between installing cabinets and doing homework I didn't get much time with my car.

 

EGR valve will kick in at > 40 mph, when the engine's warmed up, at light throttle/higher speed (such as cruising on the highway, not driving around town). If it sticks, the computer will tell it to turn off- but the valve won't close. So you'd just reach under the bottom of the EGR with your fingers (don't burn yourself- do this with engine off and cold); the EGR valve has a cutout underneath and you'll be able to feel the bottom of the diapragm. If it's stuck open the diaphragm will be "up"- meaning the valve is stuck open. The car will run poorly (if at all) when EGR is stuck open.

I'm leaning towards fuel b/c I've had many a pump die on me; your situation sounds familar. Car will smell of gas b/c the air/fuel ratio is so "wrong" that the mix can't fire. I've had pumps die where the normal "hummm" turned into a buzz so loud youd think hornets were in the tank- and I've had them die where the "hummm" turned into a sickly "gurgle". So you might be able to just go by sound; of course you should still use a fuel pressure gauge for an accurate diagnosis.

I might've said your TCC solenoid got stuck but usually (a) the car stalls when you come to a stop, and (b) after the car stalls, the TCC falls out and the car acts normal again- until the TCC enages again.

Check ignition timing too; the holddown bolt could've worked loose, and your timing would spin itself over-advanced to the point where it can't run anymore (but spark plugs would probably show signs of detonation).

Let us know what you find!

 

Here's the pictures of the cap and rotor. I had never seen the contacts in the cap corroded so bad. Replacing the them had zero effect on how the car ran though.

 

I'll definitely check the EGR the next time I get a chance then. I haven't noticed a change in the sound of my fuel pump but then again it is 23 years old now (To my knowledge it's never been replaced, I know the previous owners.). I should have changed the pump when I replaced the tank but I was a little too eager to get it on the road. I'll also check and see if my distributor is loose.

 

Funky distributor cap!!

Yeah that's the thing about fuel pumps, they start to go bad "slowly"... could be dropping pressure for years until it gets to the point where the engine runs poorly... then one day "nothing".

Check this out; my first pump died (fuel pressure gauge only gave me ~20 psi), changed it out, car still wouldn't start! Turned out my distributor hold-down had loosened up and my timing was advanced so far it was off the scale; found out b/c the #1 plug was destroyed from detonation. So not only did the fuel pump die but I'd been running on 5 cylinders for who knows how long. Once I put in new plugs and fixed the timing the car fired right up had a lot more power (I wonder why, LOL). That's why I suggested both timing+fuel to you at the same time

 

The final diagnosis was a bad plug wire on the driver side front cylinder. Absolutely no fire to the plug. Now that the wires have been replaced it's running great again.

Thanks to everyone for the suggestions!

 

I'll give you a clue about anti-seize, I have used it in the military and in the industrial applications, it is not a good conductor and if you don't clean the threads after removing the bolt and you have to remove the bolt annually you will have lock tight instaed of anti-seize in a high pressure tempature and pressure appilcations. if you like using it thats fine, but I would recomend at least removing you pluges every 6 to 7 months and clean the threads when you do the reapply, but now that you have started using it DO NOT stop if you sell the car tell the next owner.