What are some sure fire ways to tell that you need your new opti spark.
my 1994 z28 vert runs great most of the time, but recently it has been a little hard to start and when its really hot outside it will stumble and miss everyonce and a while. the other day i was racing a mustang ( yes i beat the crustang) and when we met at the light my car stumbled and then stalled. it wouldnt start back up for about 5 min. the next day i bought a jet jones perfromance chip and an slp shift firmness module. since i put those in its been great its only been about 2 days now though. it hasnt had a tune up yet and the origional opti is in it. 98000 miles on it now.

 

Not sure if there is a sure fire way unless you scan the car and get a code for a bad opti. Have a look at Injuneer's page

http://members.aol.com/InjuneerZZ/ScanMast.htm


Get a cable and scan your car with a laptop I used freescan it gave me a code 48 for MAF failure so I replaced that aswell with a used one from Ebay $65 Changing this brought back my gas mileage.

You can get a cable and free software here:

http://www.wotelectronics.com/index.html

Mine started with a stumble then 4 weeks later running like crap
I have 74,000 miles on the car

You need to make sure the basics are right, plugs, plug wires and I changed my coil and my O2's. probaly not needed

If it's your opti the car will get progressivly worse it will run like crap and eventually may not start at all!

I had to park mine up for 2 weeks until my opti arrived from the USA it was running so bad!

Now it runs better than it ever.

Best place to buy an opti is: $319 for your car

http://www.samtaylor.com/html/parts.html