I haven't posted here in a while. I think I need to remedy that problem. I did a search, and have a couple of additional questions to go along with what I found in previous threads.

My '94 LT1 has been trouble free since I got it about a year ago and with 69k on the odo. It's now sitting on 98k and over the last month or two it has developed a miss at speed.

It starts fine. It idles fine. Once on the throttle though, I can feel a small hesitation throughout the rev range at various RPMs.

I haven't personally done a tune-up on the car yet, so I don't trust/know when the last one was done. I'm thinking that will be my first step, but to that, I want to add a question or three.

Plugs and wires are easy enough to replace. Not understanding the Opti or much of it's workings other than what I've been able to read here, can you even replace just the cap and rotor in the unit? Also, with that said, is it even adviseable if the car is tore down that far to only do that much? It seems like with almost 100k on the clock, preventive maintenance dictates that I go ahead and replace the Opti with a new/better unit?

I'm aware of the accessory replacement issues, i.e. water pump, hoses, belts, etc. while I'm in there. I just want to make sure once I start to take the car apart that I don't do either too much or not enough.

I have both volumes of the factory service manual, a full tool box, and the knowledge to use them, so fire away! What's the concensus?

eta: I haven't checked the codes since the problem popped up. I'll do that either tonight or in the morning and post the results.

 

At 98k miles, you wouldn't exactly be throwing away good $ to replace the Opti now. Doing so may save you a visit from Mr Tow Truck at some point, also. You have little to lose by going for it, especially since you can handle the labor yourself. It's a tedious job, but not beyond the skills of a talented shade-tree wrench such as you've described yourself.

I would strongly encourage you to:

1. NOT even bother trying to replace just the cap/rotor. Punt the whole damned thing if you're gonna go so far as to remove the water pump.

2. NOT install another OEM Opti as a replacement. The deficiencies in the design of the first-gen Optis are well known and well documented. The replacement OEM units are no different than what was installed at the factory. Considering how much work it is to dig down to the Opti, take a good look at the DynaSpark and the new MSD unit as an alternative to the OEM item, in the hope that you won't have to dig into this again anytime soon.

A final note: The plugs and wires are not all that easy to replace, but the time to do them is while you are doing the Opti.

If you need tech tips on the Opti swap, and/or plugs/wires swap, I can post 'em here. Lemme know.

Be well,

SJW

 

What SJW said.

The wires are SO much easier to do with the engine apart like that...

be careful of the plastic wire looms, they get brittle with age.

The miss/hesitation is more than likely a plug problem, but it's best to replace the opti now, so you don't get stranded. The AC Delco double platinums are JUNK. I highly recommend using NGK plugs. I doubt you have any codes to read, either... a cap/rotor failure won't show any on an OBDI car.

 

I am replacing my Opti and there are no codes showing for me to review as well. I wish it was a code. But lots of bucking when you really load the engine under a "lug" and an idle that is slightly ruff to ruff. You keep the RPM up and she pulls the gears pretty nice. It performs a little better when cold and really goes to "to hell in a hand basket" after she warms up. Well be doing wires, plugs, hoses, WP, belt and two plug and play Cats, (4) O2 sensors and a fuel filter. Oh ya, two front rotors and pads. When I get done she will be what she was a year ago. (fast and smooth)

 

except for the NGK plugs.

 

Not only that, he's just posted the whole procedure in another thread. [see, "replacing the optispark '96 LT4" in tech/perf section] And the bit about making sure the wires are routed carefully and correctly in that thread is good advice.

From what little I know, you're going about it correctly re the things to replace at the same time: hoses, belt, wp, full opti, plugs, wires.

 

I refuse to help anyone that lives in Mustang Oklahoma!

What's going on man? If the car got 98K miles off of a single opti, that's pretty damn good in my opinion...nat a bad idea to replace it at this point, you'll likely have to do it pretty soon anyway!

Go with a GM or MSD opti, depending on what you want to spend, get some some new wires (taylor or MSD), new belt...and also inspect the waterpump very well, because if it's the original unit as well it may not have much longer to live.

Also, it'd be a good idea to swap out the fuel filter as well, they are a common issue with that amount of mileage!

EDIT: oh yeah, NGK TR-55 plugs!