Yea, Brad... I hear ya! Loud and clear!

Most interesting, tho... since I resoldered the wires and tightened the fuel rail bolt, the car has been running GREAT!

Cause/effect? I donno... cautiously optimistic...

what i know is you deserve a medal for not going postal with this problem . lets hope that you finally got a break and the problem is done with . i have been having fun with a 88 jeep cherokee that want to over heat no matter what i do .new head gasket,intake and exhaust gaskets .has this computer called renix. they used this goop to seal the connections which i found out from the forum guys melts and gets between the connections causing all sorts of problem .darn thing runs great but keeps puking water. thanx to seeing how you have handled your problem i havent thrown anything .YET . .

What wires did you resolder? Hopefully that's the end of it.

these are wires that connect the LTCC brain back to the car. Powers the coils and the EST signal. I think I outlined it 2 or three posts up.

Makes sense, solder joints can fail from vibration.

Hopefully that did it for you.

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Glad you figured it out (knock on wood)!
I dont get on here often and as I read I thought of 2 things on my 84 when it did a similar thing many years ago and recently.
Finally after several frustrating events of stumbling for no reason I could fathom mine set a code and it was a short in one of those same annoying "famous" wires hooked up to the Distributor cap/coil!

Then, 5 years ago the engine would just suddenly up and quit while driving. It would start and run great for awhile....turned out it was the stupid GM test plug also attached to the HEI! It was grounding when it hit something while moving. Clipped it off and it has run great ever since!

Another day, another perfect drive. I swear, it feels like a new car. The ride is smooth and vibration free... just amazing.

Brian - to refresh your memory - I replaced a bad connector. I used one that I thought was engine compartment certified but found out after the fact it wasn't.

I think it started to corrode internally. I snipped it off, replaced multiple solder joints with only 1 per pair and simplified the process. I think it might have fixed it. If the coils were not getting proper power, all bets are off.

throttle response is back, the car has power again... its rather shocking.

And then there is the wild card of the loose bolt on the fuel rail. The damned thing had worked out of the manifold and was standing about 1/2" above the rail! WTF? I torqued it down, too.

Well... I am becoming almost optimistic that tehe bad connector was the major culpret here.

removed same, no issues since.

Also, that bolt on the manifold... donno what to make of that.

I still have this strange gurgle sound under load, sounds like an exhaust leak, but I don't think it is; I will be working on that shortly, but I think its just burned valves and a bit of blow by under load. I do have a new PCV to put in.

Source for a harness pigtail if it helps

http://www.eficonnection.com/eficonnection/optisparkharness.aspx

That's not the type of harness... these are wires that come from the old IAC and coil harness, the Opti harness is fine.

These are the pink wires that power the coils and the white wires that feed RPM data back to the EBCM and ECM.

Can you get a new one?

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He already soldered it and repaired it...no need for a new one.

And there is NO NEW ONE!!!

It's just wire... you have to hack the connector ends off the coil/ICM harness to expose them for the LTCC feeds.

It's the power for the coil and the data for RPM. The ICM normally feeds that info by counting spark events, now the LTCC box does it.

They didn't supply a custom harness???

not for these wires.

For the coils, yes, for the opti to engine harness, yes, but these were without.

The main reason is that the harness at the coil/ICM is all back looped on itself and has the tach filter in it. The instructions require that all of that loop back and the tach filter be removed, or else it will cause issues.

Oh, and yes, I wrote the manual... really, I did.