I posted several Poor Idle postings here on the forum several months ago. In the interest of passing on some of the things I learned resolving this issue, I am posting what I learned. Perhaps it can benifit some others with the same problem:

Parts changer mode:
1. Opti-Spark including all timing cover seals
2. Wires
3. Plugs
4. IAC
5. ETC
6. TPS
7. Water pump

Still idling rough.

8.. Fuel filter.
9. Fuel Pump
10. All 8 injectors.

No change.

Bought TTS Datamaster. BLMs were showing lean. Spark changing from 19 -21. RPMs running bak and forth from 600 - 750.

Forum gurus said to look for what was causing the leanout. Couldn't find
any vacuum leaks.

Did know that I had a small oil leak out of the water pump shaft seal in the timing cover, that I replaced when I replaced the water pump.

Decided fix the oil leak. Taking everything apart again. Discovered that the oil leak was slowly leaking into the new Opti-Spark.

Replaced the Opti-Spark again with new unit, along with the seals again.

The Helms manual called for a Kent-Moore tool to repalce the water pump seal. The tool that arrived could not fit over the shaft to the water pump, which means that the tool is only useful if you remove the timing cover. Managed to get the seal on by revering the drive shaft and using the shaft to install the seal with the lips puckered inward. This was after going through all of locally available seals (5). Finally got right.

Put it all back together and it started and ran smooth until it got hot. Then started stumbling again.

Began checking the rest of the wiring system. After shaking and pulling on the coil harness, the engine stopped. Coil harness was intermittently shorting.

Replaced the harness. She ran great until hot. Started stumbling again.

Checked the forum for rough idling when hot. Some suggested spark plug wires.

The driver side on the 1995 can be accessed by removing the panel from the fender well, the intake snorkel, drive belt and belt tensioner. Began to check the ohms on the 9 month old wires. Check the ohms and number one and number eight was out of range. Replaced the those wires.

She now runs like it's 1995.

Thanks to the forum and a lot of elbow grease.

 

 

a lot of hard work went into this project...good find

 

That's why I am always skeptical when "opti" is the de-facto diagnosis. What I suspect is that during an opti change, wires are moved or replaced, connections are checked, and often plugs are also addressed. So even if something simple or cheap was the actual culprit, it looks like replacing the opti is what solved the problem. Just my $0.02.

 

That was great-just goes to show trouble shooting cost less than throwing parts at it.

 

Way to go. Just another example of "never give up" getting it done.

 

Interesting... Very interesting...

Got the same problems you describe... How long has it been behaving correctly after the fix?

 

Sorry, for not responding. I've been on vacation down in muggy Orlando. It's been several weeks and it's running great. I plan on replacing all of the spark plug wires sometime in late July.

 

The original parts changing (Opti, seals, plugs, wires, water pump) was to bring the car back to reman or like new condition. None of these parts failed. The automatic tranmission failed and I replaced it with a Goodwrench, (3 year warranty) unit from the dealer.

The goal was to get the car into a condition where it would be trouble free and reliable. I would rather swap out all of the parts at once than to spend weekends replacing the parts one at a time. The car has 130,000 heretofore trouble free miles, all on original equipment parts.

 

there is a time in a cars life that a mass replacement - a minor mechanical restoration - is in order.

Great catch on the plug wire!!!