First off I want to thank you guys for all your help with this car so far, it has helped me out alot. The reason for all these things is that these past couple of days I actually took the car out for longer and faster drives. Now I have two more problems, when the car is driven around a while but not necessarily hot and I stop at a stop light the car revs up and down(from 600 rpm to 1200 rpm) then stops for a few seconds then does it again causing be to apply extra brake power so the car doesnt start slamming into cars in front of me. Engine temperature is normal, about 220-230 for stop and go traffic. After that I got the car to fatser speeds around 50 mph when all of a sudden the started car was bogging down and would let me go past 50 mph(or 2000 rpms?). The car didnt die and kept at 50 with no problem. I tried slowly putting down the gas but then the car would shake pretty violently and bogg down. I didn't try WOT because I didn't want to break anything. Any suggestions or questions? Don't worry I will not give up on this car haha, I've had the same amount of trouble with some mustangs I used to own. Thanks

 

with milage like that i would question the catalytic converter. other than that have u done the plugs and wires yet. also look at the iac valve or motor.

 

Funny I drove it again and the whole bogging didn't happen but the reving at the light did. The cat was replaced about 10,000 miles ago or 9 years. I just bought this car and it only has been driven 10,000 miles in 9 years. The plugs and wires were replaced about 7,000 miles ago but also it has been a couple of years. Also the opti has never been replaced, is this the issue?

 

The opti could potentially be the problem, but then again a lot of things could be...

The bouncing revs at the stoplights remind me of an issue I had about two months after I bought my car. I'd be at a stop, and the surging at idle would almost push me into whatever was in front of me. And when I'd be cruising along, it would seem to lose power and sputter and sometimes misfire. I took it to our garage and our mechanic asked me how I drive the car. I answered honestly, and told him I drove it like a grandma (one WOT per fill-up, and other than that I'd be below 1800 rpms at all times). He told me that carbon build-up is a fairly serious issue with these cars if you don't go out and stretch their legs very often. We were standing in their parking lot, and he just revved the **** out of it for ten seconds, and it cleared right up. He told me that the best way to take care of these cars is to drive it like it's intended. So, I do. And I get better gas mileage being 'rough' on it than I did before also!

 

I pretty much drive the way you described. I rarely go WOT lol, I'm going to check out the IAC and throw in some BG44K and run it hard.

 

My 94 Z28 has about the same mileage and here are the things i've had to replace in the 10 years that i've owned it. I originally misdiagnosed the first major problem after a fouled plug clogged the cat. Never thought about the opti. Then, the EGR went out and caused very crazy driveability problems. Lots of sputtering and bogging down in certain mid level RPM ranges. Then it ran way rich which of course ended up screwing up another cat. Once again, never thought about the opti. Then, after i had a melted plug wire i finally got smart and decided to replace the opti. My mechanic buddy looked at the old opti and wondered how the car ran at all. I replaced it with an MSD LT1 distributer and things are good now. Except that i tear up the exhaust now and again. Still trying to get used to the car sitting lower. Anyways, i don't think that the low mileage is a major cause of your issues. I think that parts just wear out as time goes on. And for goodness sake, change that crazy opti!!!!!

Garry

 

i had the same idle problems and unfortunatly its most likely you opti....that was my problem i say check your cat and you fuel filter along with all the other things suggested. if it is your opti you will most likely start hearing it miss a lot then it will backfire and start randomly dying on you... if you get a ses light on run your codes and see if it says your opti

 

Do I have to pull the cat to see if it is bad and if I do what does a bad cat look like?

 

First, I would check for any stored error codes. You could have some, even if your light isn't on now.
I just finished replacing the opti in my "other" car, and it made a world of difference (I knew it would by the codes I pulled).
The engine would start at the touch of the key. But sitting at a light, the engine would sputter and the car would actually jerk back and forth. And since the engine was running rich due to the misfire (or no fire), the sensors would make the computer try to compensate, and the idle would pick up and make the car want to creep. If I idled it long enough, the left cat would start to turn red (a sure sign of a rich air/fuel mix). For fun, take a look at yours while idling in the dark, and see if you see red. Mine has 98k miles, and the innards of my opti looked like crap with rust and corrosion everywhere. It's a common problem with these engines because the inaccessibility of the distributor makes "regular preventative maintenance" non-existant.

 

your cat would just be clogged you can take it off and clean it, or i suggest gutting it for better flow....you can also purchase a hi flow cat. i agree tho check for any stored codes first thing...