Yesterday while I was out on a drive the car stuttered and stalled. The Service Engine light came on and off. I got it restarted and it did it again a couple of blocks later. I finally managed to restart and got it home about 5-7 miles from where it stalled with no further incident. When I got it home I started and stopped it a few times without a problem, no service engine light.

This morning I got out the papeclip and this is what I got:

[COLOR="Blue"]1.1 - H74 - LED Display Open [/COLOR]- I have no idea what this means
[COLOR="blue"]4.1 - H16 - Opti Spark Low Resolution (Fuel)[/COLOR]
[COLOR="Blue"]4.1 - H36 - Opti Spark High Resolution (Timing)[/COLOR][COLOR="Black"]

Right now the car is turning on without a problem and not throwing any codes.

Could this have just been a one time thing or am I destined to have to replace the Opti? The PO had it replaced along with the water pump right before I bought the car 4 years and 12K miles ago.[/COLOR]
Any info is appreciated. Thanks

It doesn't look good... BUT... check that the wiring to the opti isn't damaged in some way.

If the harness to the opti is bad, it will cause the same codes. I have heard that ppl have experienced these codes when things corrode.

I would wonder what Opti the PO put in... Was it a new GM unit or was it a sketch reman from Autozone? If it was a reman from Autozone, I am shocked it lasted this long.

So far it seems to be working. I think tomorrow I'll try to work up the courage to take it on the road and see how it goes. If it gives me trouble again I'll start on the wires

I have the records from the po that he got the work done at a chevy dealer so I have to believe that they used a gm/delco part.

Thanks

Interesting that the SES came on and off with the 16 & 36, I'd think it would stay on untill the codes were cleared which seems to be happening.
I wonder how long those codes were stored.

Yea, definately run it again until it goes into closed loop.
It could be a totally different problem especially if it doesn't throw 16 & 36 again.

H-74, It's part of the dash display that dims the LCD.
I wouldn't worry about it. My 92's been throwing that code 4 times a year for 5 years. It's not worth my time to go after it because everything works OK.

I need to clarify my "wire" comments. I mean the harness to the opti, not plug wires. Plug wires will NOT cause the codes to appear.

Gotta believe the codes were fresh because the ses did flash while this was happening

Quote:

Once the codes are in there, they will stay until cleared or the battery is disconnected. If they're not cleared, they could be in there for years (whatever).

The only to know if they're current is to clear them which I believe you did.

I'm still puzzled by the flashing SES, The 16/36 should have kept it on, at least, until you turned the key off and back on.
Good Luck

Ok, I actually opened the FSM,

"In the case on an "intermittent" problem, the SES light will light for 10 seconds and then go out. Codes will be stored."

So, check all the wiring from the opti to the ECM like Andy said.
Make sure the codes are cleared and do the run you were going to do. And recheck for codes.

another vote for the harness

OK. I checked the connectors and I don't see any obvious signs of corrosion or any nicked wires.

It finally stopped raining so I took it out for test ride today.

Started up like a champ. No SES. I waited till it got good and hot and I took it around the block a few times. Not stuttering, no stalls. I figure I'll get braver over the weekend and take it for a longer drive and see what happens.

Thanks for the posts and suggestions. I'll update over the weekend.