My leading plugs have the normal light carbon coating, but after inspection the next day I notice light brown spots on them.

My trailing plugs...well...one looks ok. Coated a little more than the leading,...

... but the other is caked with it. The grooves are filled and much dirtier than the others.

I might be down on power, but I'm not sure.The car was running like crap one day and settled down, but I might just be injecting my own negativity in there because of that.

I need to find out what is causing it either from you or a source you know of.

 

You may have a bad wire. Try replacing the plug wires and then look at the coil that the plug runs off. It may be cracked or need replacement. If it happens even after you replace the coil or the coil has problems again after replacement there be a burned out coil driver in the ecu.

 

Yes, zoomzoom is right. It is either a bad wire, coil or just a loose connection. I did that once and noticed my A/F gauge was acting funny.

 

I replaced the wires. I did not see any obvious damage while I was in there, but then again i was not rally looking that deep. Just in the area where the wire attaches.
Will i have to pull the plenum off to look for a damaged coil?

 

You can't really "look" for a damaged coil because the damage is internal (unless it caught on fire) ... and yes, you'll have to take the manifold off to get them out. Two of them are in a metal tray/box thing, and another one attached on the outside. And a bad coil can actually test good, believe it or not.

 

Actually you can usually see a crack in the outside plastic of the coil thats fried. Usually when a coil driver goes bad in the ECU it will cause the Coil to stay on and in tern it overheats causing it to fail soon afterward so the outer shell will most of the time have an obvious crack in it.I did this same repair job to Ray Lockheads car. If thats the case your also looking at replacing the ECU unless you can repair it. Repairing an ECU means pulling the power and control boards out and removing all the potting material using a soldering iron take loose the coil drivers and replace it with a new one. I dont know what it would take because I have never repaired a stock ECU only TEC units made by electromotive. Also you will need to fix any burned out traces on the boards then re pot the boards and after its dry try it again. This is only if you can get your hands on the right coil driver. otherwise just buy another ECU if you have determined its bad.

 

[QUOTE]Originally posted by ZoomZoom
Actually you can usually see a crack in the outside plastic of the coil thats fried. Usually when a coil driver goes bad in the ECU it will cause the Coil to stay on and in tern it overheats causing it to fail soon afterward so the outer shell will most of the time have an obvious crack in it.I did this same repair job to Ray Lockheads car. If thats the case your also looking at replacing the ECU unless you can repair it. Repairing an ECU means pulling the power and control boards out and removing all the potting material using a soldering iron take loose the coil drivers and replace it with a new one. I dont know what it would take because I have never repaired a stock ECU only TEC units made by electromotive. Also you will need to fix any burned out traces on the boards then re pot the boards and after its dry try it again. This is only if you can get your hands on the right coil driver. otherwise just buy another ECU if you have determined its bad. [/
QUOTE]

This makes it sound as if coils don't simply fail. I checked my records and I had the number 2 (thats the rear rotor, right?) trailing coil replaced 11,000 miles ago at 89,000 miles. That is the plug that is caked up very badly and the one I suspect is not working.

Digging more ...it seems I've replaced a leading coil as well...record doesn't indicate which.

 

If you have recently replaced this same coil its almost obvious its the coil driver in the ECU blowing them out if its happened again so soon after replacement. It probably happned the day after you replaced it. Its hard to trouble shoot. It may be that you lost a seal on the motor on that rotor and its caked up on your plugs. Look at both sides before you buy a New ECU.

 

Wouldn't that have affected both plugs or no?

 

I checked for error codes ...my first time. I was watching for the check engine light to blink...nothing.
Thats the right one, right?
Anyway, no lights that I saw flashed.
I think I replaced the battery after having the the T2 coil replaced so they may have been cleared...but that was over a year ago.

 

I ran the 40-70 in 3rd gear test I described in my other post and it seems that I am indeed missing HP.

Using a stop watch I did three runs with my stock 93 Touring with 100,000 miles, 3/4 full fuel, and the temp here was 88 degrees.

1. 6.1 sec ...with my wife in he car too.
Dropped her off and went solo...
2. 5.5 sec ...felt as if I hit the trigger to early?
3. 5.7 sec ...that one felt like I slipped on the trigger
4. 5.6 sec ...felt about right, but I hit a very slight uphill grade at the end

Well unless I see some similar times, it looks as if I am down in power as I suspected.

 

Was it idling bad or missing on top end WOT ? Did you end up changing your coils or what? If so, how much did it cost for the coils?