okay, ive read the sticky on the diagnosing the opti, but im not good at that kinda work, so im hoping someone else has had similar symptoms and can give me some advice.

my car has been "stuttering" or cutting out at wot once i get about 4K rpm. it has gotten progressively worse with time. also, it seemed to be worse when i hot lapped it at the strip.

the best way to describe it is that it feels just like when plug wires go bad and the motor is under a load at low rpm. except its at the opposite end of the rpm range.

my opti is the stocker that came on the car so i figured ive been fortunate enough for it to last 78k miles and nearly 14 years....

anyone think of anything else it could be, or other things i should look at? everything else seems to be fine. AF ratio isnt going lean or anything so i dont think its a fuel issue (im actually on the rich side).

thanks guys,
Jeremy

 

The opti is a DISTRIBUTOR as such it has a cap and rotor that WEAR like any other distributor. A HUGE part of the opti's bad reputation comes from folks not being smart enough to comprehend the cap and rotor are TUNEUP items and try and leave them on indefinetely and then blame the parts for their neglect.

 

i think what he is saying is the first thing you should do is change the cap and rotor, that is what it sounds like to me. i am using the msd unit and like it

 

Replace:fuel filterfuel pump
opti cap & rotor
plugs and wires

 

If you have a weak ignition, faulty wires, faulty plugs, etc., the first place its going to show up is at high engine load, higher RPM. That's when the engine puts the most stress on the ignition system.

First, have you scanned it for codes? The Opti produces codes for problems with the optical cam position sensor. There are codes for problems with the IC module and related coil problems. Your 96 also has misfire detection, and using a scanner with GM enhanced parameters, you can read the misfire count by individual cylinder. Those numbers might point to the problem, and whether its a "general" problem, or specific to certain cylinders.

Weak fuel system also has to be investigated. Have you checked the fuel pressure with the engine under max load/max rpm?

 

i have not checked the fuel pressure, but ive got a WB o2 sensor and my AF is actually butt rich because im still running the FMU and inline pump that came with the vortech kit. YES, i do plan on ditching all of that for big injectors and a walbro in-tank pump.

i didnt figure it was the plug wires because they are pretty new with low miles and the symptoms i had when i put the new plugs and wires on was a hesitation under a load at low rpm. the low end hesitation smoothed out at higher RPM. and obviously, plugs and wires fixed the problem.

oh, and my plugs look fine. i pulled them all out and checked them.

i have scanned for pending trouble codes with my hand held reader and it showed nothing. i'll have my father in law check it with his tech 2 and see if he can see anything.

thanks injuneer. ive never had any hesitation at higher rpm with bad plugs or wires, but ill look into that further before buying a new opti or icm.

the only thing that sucks is that it will take me just as long to change the plugs and wires as it will to change the opti. ive got to pull the front sway bar, fans, and drop out the blower to do a wire change...not hard, just annoying.

 

I have had high rpm miss w/ LT1 opti spark.
Most recent... gm opti got fowled inside. Some type of fluid (I think coolant).
I have also had opti failure from the encoder (A summit opti). Total loss of ignition when it was @ temp. Restart @ pressure application @ connector. I think an open in the encoder electronics since I had good pin engagement.
Also had high rpm miss when there was alot of timing advance (adjusted and fixed with an all-ignition.com performance opti).
I have had 3 failures of the spark distributor rotor. I fix with two (2) alum rivets to secure the brass electrode. No failures since use of this mod.
B. (app... 97ss 383 - D1 MM6)