I have 150k miles on my Z28 and it has started to stumble at low rpms, especially with a high load. If I downshift it performs great. I still have the original opti but I have replaced the spark plugs and wires. I hear everyone saying that the opti can cause problems like this but is there any way to know for sure that is the opti? How long does the opti normally last? My car is totally stock with the exception of the exhaust and K&N air filter. Any help would be greatly appreciated.

Mike

 

Sometimes it’s very hard to tell if it’s the opti unless you replace and check everything else like coil (and coil wire) ignition module. Ground wires etc. but it’s most likely going to be the opti from my experience if everything mechanical is in good working order. You can know get them for under 200 (new and complete) If you decide to get one let me know and I will send you a couple of links to go to.

It real easy to take off:

1 Take water pump off
2) Remove balancer (not the hub)
3) Then unbolt opti form timing chain cover.

It should take you about an hour to pull it on and off.

 

Sometimes the EGR will stick partly open and that causes slow speed problems but it gets better with higher engine speeds. It's easy to check and clean if it is the problem. Saves buying things to try to find the problem.