Need Help With An Engine Miss

[97 Zee]

Hey Guys, Ever sence I replaced my optispark and water pump a few months back I've had this miss at higher RPM's, usually after 4000. While driving around in city or even on the thruway if I dont get on it hard the car runs just fine. But the moment I go to full throttle and the RPM's get above 4000 I get this anoying and very noticable miss. I've replaced the plugs and wires and no change. One thing that did happen after I made the switch was, my water pump was leaking but just a little. I found the leak and fixed it. It wasnt like big puddles or anything it was just little spots under the car after I shut it off. My question is, might that little leaking have runed my new opti? Can a Opti react like mine is? Just missing at high RPM's? I'm really thinking not but I dont know where to go from here. The Opti was brand new from Dale Slabaugh. and I did replace all the related vacuum hoses going to it as well. Could it be the coil? I was thinking about putting the old opti back in today to see what happens but thats a job I would like to avoid if anybody has any other ideas. It does seem however, like too much of a coincidence that the miss arrived just after I put the new opti in. Anyway... My head is getting pretty sore from beating it against the wall so any help would be greatly appreciated.

[Joe 1320]

Hey Guys, Ever sence I replaced my optispark and water pump a few months back I've had this miss at higher RPM's, usually after 4000. While driving around in city or even on the thruway if I dont get on it hard the car runs just fine. But the moment I go to full throttle and the RPM's get above 4000 I get this anoying and very noticable miss. I've replaced the plugs and wires and no change. One thing that did happen after I made the switch was, my water pump was leaking but just a little. I found the leak and fixed it. It wasnt like big puddles or anything it was just little spots under the car after I shut it off. My question is, might that little leaking have runed my new opti? Can a Opti react like mine is? Just missing at high RPM's? I'm really thinking not but I dont know where to go from here. The Opti was brand new from Dale Slabaugh. and I did replace all the related vacuum hoses going to it as well. Could it be the coil? I was thinking about putting the old opti back in today to see what happens but thats a job I would like to avoid if anybody has any other ideas. It does seem however, like too much of a coincidence that the miss arrived just after I put the new opti in. Anyway... My head is getting pretty sore from beating it against the wall so any help would be greatly appreciated.

Yes,Yes, Yes and Yes.

However, I would suggest checking all the harness connections on the coil and the driver module first. Issues with those have been known to cause those symptoms too.

[Injuneer]

Also check the harness connectors for the Opti, both the connector that goes on to the Opti itself, and the gray connector on the bracket on the passenger side of the intake manifold. Check the plug and coil wire terminals in the Opti for corrosion.

As Joe notes, the coil of IC Module could also contribute. The voltage required to fire the plugs increases with engine load. Push down on the throttle, engine load goes up and the plugs require more voltage. The voltage isn't making it from the coil to the plug. The coil, the Opti, and the plug wires are in between. So one of them is contributing to the miss. Unless the miss was always there, hidden by the earlier, faulty Opti. In that case, it could be anything, including injectors, sitcky lifter, etc.

[97 Zee]

Thanks for the input guys. I decided to just go out and replace the Opti. This is before I got your messages. I put the old one back in, that had about 80,000 miles on it and it worked fine, the miss was gone. However, I did notice that the little tab on the ignition module that locks the conector to the module was broken off. Im not sure when it happened or if this was a contributing factor to the problem. I'm guessing as long as the conector is pushed in tight that wouldnt create the problem I was having. Its been quite a while sence I put in the new Opti and the problem has been there ever sence I did. ANYway.... I tie wrapped the conector on to make sure it wont come loose or fall off, Until I can replace it. It sure feels great to get to 4 grand and it still pulls pretty hard with no miss. By the way I started at about 1:00 and I finished about 6:00 thats with 4 trips to the auto parts store. I think I did pretty well. Not too much blood loss and every things still attached. lol. These cars are such a joy to work on.

[97 Zee]

One more thing, When I went to put in the old Opti, I noticed the two little shaft seals were dried out and falling off. So I decided to take the ones off the newer Opti and install them on the old one. Well, those broke when I tried to carefully remove them. Trying to find the exact replacements was imposible late on a Saturday. So I went to the local hardware store and found a couple of o-rings that were very close to the originals. They were rounded edge instead of flat like the originals but fit good in the groove and seemed to install nicely into the cam. I do plan to replace the Opti in the neer future so I thought these seals would serfice until I do. Do you think these seals are ok? Or did I do a Baaaad Thing?