Well,excuse me for trying to get some input! I guess anyone who has an LT1 with 100K miles and a hesitation should just buy an opti and do all the labor thats involved or better yet give a shop $1000+ to change it without second guessingI thought that was one of the good reasons why boards like this exist,to share ideas,so those of us that are mechanically inclined and are willing to take the time to fix our cars probs ourselves,can save the $ a shop would charge. I've had this problem going on 2 months now and no one can explain WHY its the opti,just that "they go bad"BTW,like I said,I replaced the plugs wires and coil before I had this problem,and I just recieved my opti today and paid an xtra $30 for overnight so I could get it by the weekend because of the holiday and drove 100 miles to my parents house to work on it(cant do this $hit at my apt complex)Hopefully it runs better after I change it and the waterpump(might as well) but I still think I might need new PCM as well but I am going to be pretty and if it runs the same.

 

Hey let us know how it goes!!

As for my car, it's going into the shop on Monday to be looked at. I took it to a different shop, that I have never been to before, but I hear they do really good work and there is a guy there that knows his LT1's really good, they said they have heard of this problem alot before and they say they will be able to fix it.......we will see........I will let everyone know what they tell me!!!
wish me luck!!!

 

Most people cant grasp the fact that an opti is still a DISTRIBUTOR, with wear items such as a cap and rotor. The materials used in the opti are superior to typical distributors, but they are wear items regardless. A typical distributor cap and rotor gets replaced every 30-60k miles, depending on the quality of the materials used. An opti is ready for replacement at 100k miles. Not only do the cap and rotor wear out, the bearings dry up and wear also. The optical sensors become contaminated with oxidation.

I made the mistake of waiting till 160k miles before replacing mine. The car ran lousy those last 60k miles, and I ended up melting the CAT.

So even if the opti is not the main cause of your hesitation, it's contributing to it, and is due for replacement anyway. It was designed to meet the 100k mile tune-up interval, not the life of the car.


Good luck!

 

Well I changed that SOB today, took the old one out and I could hear a "grinding"when I turned it.The whole job was about as fun as replacing a bent pushrod and collapsed lifter(whoops)in my 94 Z.Not to bad except getting the gasket $hit off the waterpump,althogh I had to rent a puller to take my balancer off,just time consuming(about 6 hours)Anyway,the low rpm stumple,knock,so far is GONE I even got the temp up to 220+I don't know exactly why resetting the comp fixed the problem for alittle but that problem seems gone,i guess my PCM is okay and the dealer was trying to rip me but,I still have a high rpm miss,roughness.I am going to check all my plug wires tomorrow to see if any are burnt or crossed.Is there anything else that would just make the car all of a sudden seem louder,miss,and feel rougher?

 

Were map sensors only put on 93's.After having my intake manifold gasket fixed,and map sensor replaced,did my car run smooth.No more gunked up plugs,off idle stumble,fights with the wife,grass is greener in the front yard,city finally fixed most of the pot holes around town.Really though,Maybe the computer needs to be flashed(read that somewhere on previous posts,but don't know what it means),but I do know all the wires on a ten year old car like mine are toast,and you can take that to the bank.In other words,maybe info isn't being translated to the computer correctly.Well, my beer is getting warm,so time to ice it down again,darn heat here in so cal is around 100.Hope this helps.(No heat sink here so far this year.)My02

 

Yes .....yes More Replies....come one someone has had to solved this mistery!

 

My mystery has been solved,with a new opti and...a burnt #7 sparkplug wire

 

i have the same prob.......just happened a month ago and has been in and out of the shop.......they changer the egr valve first......then the said wires....they changed the wires and ran perfect.....but then i look under the hood after i get done driving it home and the wires are laying on the bottom side of the header so it is acting up again.... stumble and misses......think it might just be the wire though.....i hope

my car does have 120,000 and don't think the opti or pump have been replaced.........but here is a question.......if i plan to get a crate motor do i need to replace the oti or the water pump.....or do they come on the engine......i don't have any knowledge or crate motors.

It's going to be a 396 from neu-tek with some real goodies in it

 

So it's really fixed??? It doesn't act up at ALL!!!!!

Well I get my car back from the shop tomorrow, they told me FOR SURE it is a ignition problem and that my Plugs, Wires, and Coil are ALL good, they are pulling apart the Opti to see how it looks, they said it HAS to be a bad opti going bye bye........

 

*adds his name to the list of people with this problem*

*takes a seat*..

I .. have a problem.. my car.. runs like a dream when its cold but when it gets to operating temps for a few minutes and I stop for a while it will give the grumble (tach goes up and down a little)... I call it the oh **** grumble cause as soon as it does it.. it.. yes you guessed it runs like ****.. everyones heard the problem 500 times in this thread so heres just one more vote for a solution.. I would give 1000 dollars if my car was totally fixed tommarrow..

 

The reason these cars run good when they are cold is that:

IT IS RUNNING IN OPEN LOOP YALL!!!

The PCM doesn't listen to those O2 sensors until they warm up and the car has been running for so long. Then the PCM goes into closed loop.

Most of these problems that we are having is plug wires. If the spark doesn't get to the plug, air and fuel passes right through the engine. In the exhaust sits these wonderful O2 sensors. O2 sensors only monitor OXYGEN, not fuel. So if it senses oxygen, it tells the PCM to leave those fuel injectors open a little bit longer for some more fuel to burn up that oxygen that it is sensing, not knowing that it is unburned fuel and air in there. Rich conditions exist now, giving us poor gas mileage and running like a pig.

Spark plug wires have a bad tendency of arching under heavy loads. If you stomp the gas, that plug wires archs, and the stiuation occurs. If you're slowing down to a lower speed limit with your foot off of the gas and press down on the throttle, MISFIRE (due to dif. in load) the situation happens again.

All of this happens ONLY WHEN IT IS HOT! Closed loop. Feed back from the O2.

IF you have new wires and you're sure it it not your wires, then look to OPTI.

Hope this helps yall

D Moss

 

I think this was the most informative post of them all!!!!! gimme more of em!!.HAHAHAHAHA

 

We have almost certainly isolated the problem on mine as the number 7 wire. It was touching the bolt where the header flange meets the y-pipe flange. As the car heated up, problem started. I've insulated the plug wire, and have had NO problems since.

Try this one, everybody!

Marcus

 

Hey guys this is a real problem. Add me to the list of the normal running temp problem. (2 years) now this is crazy.I feel Satanaz666 pain I am so pissed off it is crazy my gm dealer told me it was maniflold leak which was leaking on the opti. I hope someone figure this one out.

 

Nope,I spoke to soon and jinxed myself I changed the damn #7 wire,took it for a drive,all the power and smoothness seemed back but the temp didnt get to hot.I didnt want to go through this again so I took it off agaain and wrapped some header wrap around and tied it, put it back on drove to Tampa from orlando,and as the car got warm I could feel A SLIGHT MISS AGAIN that seems to start at about 3000rpm,now I'm stuck with jacking it up at my apt complex with my tire jack to try and figure this $hit out.