cpayne

After changing the drivers side coil wires three times with used ones because of fireflies and rough running, I put new coil wires on about 1 month ago and the car has ran well until last week.
When the car is started for the first time it runs rough. I thought maybe the wire was arching on a bolt head as in the past . I switch the car off and move the wire away from the bolt head stat it again and it still runs rough.
I bought some wire covers from NAPA and put them on the coil wires. Same thing. Caps and buttons look good.
The weird thing is that after going about 6 miles and the temperature is at normal for this car, I feel the power comeback as it feels like all cylinders come on line.
I have pulled over and opened the hood and the wire is near the bolt. The car runs great. I can switch the car off and on and it runs well. The only time the poor performance returns is if the car sits all day at work. At about 6 miles and at temperature the car smooths out. I have confirmed the 6 miles and temperature 6 times.

Any ideas?

soupcan

Leaking injectors

daveo90s4

Does your cat have cats and the ignition monitoring system?

the flyin' scotsman

I also had poor running conditions when cold........overnight or all day cold...........the hose to the ISV under the intake was split.

After the car warmed up it ran perfectly.

cpayne

Thanks guys. I have had some ISV issues. Looks like intake refresh and some ford injectors are on my list.
I'll guess I could try fuel injector cleaner first .

cpayne

I don;t know the answer to that one. I'm kind of a newb.

Stromius

No only 89plus have this. It's a light at the LH & EZK modules that show limp home mode.

Stromius

C - have you looked at the coil grounds to see if the wires are ok? I recall a post some time ago where there was a break inside the insulation. Also are the coil contacts corrosion fee esp passenger side? Just a thought before you throw $$.

Lizard928

inspect your front of engine harness for problems in the wiring. IE frayed, or damaged insulation.
I have seen a harness or two that causes this.....

JoeTaylor

I have worked with high voltage (electrostatic separators) and when I read your post, the first thing that came to mind was - moisture.

All plastics absorb moisture from the humidity in the air to some extent or another. Some plastics are more hydroscopic than others

In my former business, we were very familiar with the phenomena here in humid Florida. The mantra is "tempurature cures all".

Once the ignition wire(s) heat up, the surface moisture on the insulation starts to dry off. So when the engine is hot, the heat of the engine drives off and keeps away the surface moisture.

Next day, after the engine cools overnight, the moisture from the air absorbs again into the insulation.

The way to check this is to use a hair dryer and dry off all the wires while the engine is cold first thing in the morning. The wire insulation should get hot enough you can feel it with you fingers... but not too hot. Then try cranking up your engine.

If the problem goes away... haha, blame it on the dew and humidity.

Joe

AO

Have you pulled your spark plugs and looked at them?

When it's running like crap, shut off the engine, and pull the plugs. You should be able to tell which cylinders are the culprit and narrow it down. If it's all 4, it's either the cap, rotor, coil, or final stage (the thing that's at the very front of the engine on the driver side).

If it's just one or two plugs, then it's further back (although the cap and rotor could still be suspect).

WallyP

The Temp II Sensor may be faulty. On the top of the engine, near the front just off of center, there is a sensor screwed into the engine, with two wires in the harness. There are two identical temperature sensors, one for the ignition and one for the injection. Check the resistance of each pin to ground not from pin-to-pin. The resistance at specified engine temps should be:
32 deg F - 4.4 to 6.8 kOhms
60 to 85 deg F - 1.4 to 3.6 kOhms
104 deg F - 0.9 to 1.3 kOhms
140 deg F - 480 to 720 Ohms
176 deg F - 250 to 390 Ohms

fraggle

How new are the plug wires? Based on the moisture/high voltage experience input, maybe a set on the way out is more susceptible. You just moved the problem from the coil wire up to the sparkplug wires.

cpayne

I checked those out. I cleaned those grounds not to long ago. I'll take another look however. I remember some wires When we did the timing belt we did wrap the portion of wires that run behind the PS res with some self vulcanizing electrical tape. I may have to add harness rebuild when I do the intake R/R as it needs to be done after seeing some serious wear on some of the sheathing.

Jadz928

Let us know what you do to diagnose this. Could be an easy fix, who knows. Keep us posted.