Nickw059

If you start up my car cold, it seems too run good . If you drive it around for about 30 min, it will sputter for a second than die. than you start it up, it will sputter and die. Than if you let it set for around 15 min, it will fire right up, than you can drive it around for a while than sputter and die. it seems too do good when cold. when it sputters and dies the service engine soon comes on, it gives me codes 16,36,42, and 33. If you clear them they don't pop back up until you drive around a while and it dies. what do you guys think? cna the opti have "Burps?" how come when you start it up cold it runs good? I'm plannign on replacing the opti, and ignition coil, but I'd like too know "Why" its doing that.

'94 Bad A Z28

From my experience that is always the sign of an opti being bad.

Injuneer

It's possible that the optical cam position module in the Opti is heat-soaking, and only breaking down after it reaches a high temperature. DTC 16 and 36 indicate the signal frm that module is not reaching the PCM. That could be caused by corrosion at the Optispark harness connector, although it's hard to tie that specifically to the engine running for 30 minutes. But it's worth a check of the harness connector.

Similarly, the IC module may be heat-soaking and breaking down. That would explain DTC 42, but not the two Opti codes.

Then there's the MAP sensor code. Can't think of any logical reason that would show up simultaneously with the other three codes. The Opti and the MAP sensor both get their reference (or power) voltage from the "B" connector on the PCM. Long shot - but maybe a PCM or connector problem.

Inspect the MAP sensor harness connector. They tend to dry out and crumble, causing intermittent MAP readings. Again, hard to relate to the other three codes, or the seemingly consistent 30-minute run times.

jloshotz

For what it's worth, this describes the problem I was having with my first 4th gen (also a 95 Z) to the letter, when the opti was giving out. I actually purchased the car in the winter, and it never had a symptom. As soon as spring rolled around, the car would get me anywhere within a 15 minute or so drive, then it would die and leave me stuck, cranking but not starting. 15 minutes of cool off.....yep, would fire right back up and run normally, for about another 10 minutes. Luckily I only had about a 13 minute commute every day, so I'd usually make it lol. I was in denial over it for a bit, due to the cost of the opti, I did the ICM mod, hoping.....no luck. I finally scored an OEM Delco opti on eBay for a reasonable cost and bit the bullet. Presto, problem solved. Now, be sure to do your homework, as this is just my personal experience, but it sounds VERY familiar.

shoebox

The MAP code could be a result of the engine dying unexpectedly. The computer thinks the engine should be running, but gets low vacuum from the MAP and sets the code. 42 often accompanies 16 and 32. I'd say things point in the direction of the opti. Make sure you check the harness first.