Missing Taurus

[carrera79]

I just did a tune up on my girlfriends '97 Taurus, 12V V6, because it was idling a little rough and was throwing a code for a miss every once in awhile. I changed the plugs and wires, and it's still missing at idle. What are the possible issues? Do coils go on these cars (one coil pack for all cylinders, that I did check by spraying with water in the dark, no spark)? Could the plug wires that I bought (new motorcraft) be bad? Could I have gapped the plugs incorrectly (I doubt)? this is really getting too me.

 

[thrace]

Had an '89 Vulcan 3.0 which missed due to dirty fuel injectors. No codes but it did not have OBDII. It missed badly and backfired even after new plugs, cap, rotor, wires. Spark was good and fat. Problem was clogged fuel injectors. Used Techron FI cleaner all the time for over a month and problem improved but did not go away.

 

[eljefino]

I'd clean the fuel injectors next, techron or BG44k is good. Check for vacuum leaks, bad pcv/egr valves... How is the car at speed?

 

[JTK]

This also could be a leaky intake manifold gasket causing air leakage at low throttle/high vacuum conditions.
G/luck
Joel

 

[darkdan]

If you can get the FI off it might be worth having them professionally cleaned. I can't remember the place, but there's a few sites online that will clean, balance, and blueprint your FI for $20 to $25 each.

 

[carrera79]

Thanks guys, you really seem to think it's a fuel problem. It only misses at idle. At speed it's fine either just cruising or under load. Before I did the tune up it was missing badly going up hill under power. This is a very poorly maintained vehicle except for oil changes. It's amazing how nasty the coolant is. That's coming out in the next week or two. I think that I'm going to attempt a techron cleaning with lots of Neutra after that.

 

[K-Man]

Carrera79, check your oil and coolant thoroughly for signs of head gasket failure, especially since you say that the coolant looks bad. Check the exhaust for white smoke on idle.

My Escort just had a head gasket failure at 242K miles. I caught it in its early stages. The car idled rough, causing a check engine light with the code for cylinder 4 misfire. It ran fine on the highway, though, and I replaced the coil pack since it was out of ohm specs. But it turned out that the idle problem didn't totally leave, and about this time I noticed the white smoke. The car never overheated, and the temperature gauge always read normal.

Coolant never got into the oil so far as I could tell on the dipstick, nor did oil get in the coolant. The coolant was leaking into cylinder 4 at idle, but the pressure in that cylinder built up at speed to eliminate the white smoke.

Just my $0.02.

 

[Kestas]

Have you cleaned the throttle body bore? This has a significant impact on idle quality. It's just an easy cleaning process so it doesn't cost anything to do, and may fix the problem.

 

[carrera79]

ekrampitzjr you're killing me here. I have noticed that the coolant seems to drop over the period of a few months (I don't care to look at an abused car all that often) It's not smoking any appreciable amount that I've seen, and it's still a strong performer (for a Taurus I guess). I think I might get a compression test done on it.

Kestas- I'm definitely going to give that a try.

Thanks for all of your help and opinions. This poor and abused car needs some TLC.