Im really at a loss. I got in the car yesterday and decided to go for a cruise after work. Well im out cruising and decided to jump on it while merging into traffic. But in doing so at about 3500 rpm's i got a huge hesitation/miss that felt like the whole car just turned off for a split second. Then it made a loud pop.

I thought it was weird so i tried again. Did the same thing only at a higher RPM.

Then as i started driving around town i noticed that it was almost wanting to die when id just slip the clutch with very little gas when taking off from a stop.

Lately ive been noticing a little cam surge, and the other day when it was raining the surge was real bad. My A/F ratio on the dyno last month was a 10.8 to 1 yeah, bad i know. But i dont think its the reason for my miss now.

Then last night i tried playing with a C3 vette just because the car felt alot better. Wrong! Middle of 2nd i get a huge backfire and decide not to play on it anymore. Till this afternoon when i was merging onto a busy interstate and had to give it some go juice. Though it wasnt the huge 1 second long hesitation it did start bucking at 4K+ rpms. I almost feel like im flooding the engine or something.

I changed the plugs about 3500 miles ago, wires have 50K, opti 70K(im thinking opti), and 02 sensors who knows(though at WOT this shouldnt matter).

One thing that is bothering me is a miss shift the other day 2-1 (6 days ago to be exact)

But i dont think that would have a delayed effect on my car.
It also feels like its worse the higher the gear that im in. Though i really havent punched it in any gear other than 2nd.

The car has never been tuned and the mods are....

94z28 M6, AS&M CAI, Coated MAC headers/off-road y-pipe, 3" cut-out in place of the cat, slp 2OTL, MSD coil, free mods. The rest of the mods are all suspension/chassis etc...

Help!

 

could be the opti but usually when the opti starts ****ing up it throws a code..... You also said that your wires had 50 k on them... that could be the problem.... You are supposed to replace the wires every 35 k..... i say you replace them before anything. Hope you figure it out....


Chris

 

That's exactly what my opti did for a few months before it finally gave up and just died. Symptoms I had included:

1. Horrible fuel economy

2. Hard starting

3. Occasional backfiring when starting

4. Any revs past 4k and it would start breaking up and backfiring, almost like I took my foot off the gas.

 

No backfiring when starting, but bad fuel economy, revving, and occasionally it takes 2 seconds to start.

And you described it best when you said it felt like you took your foot off the gas for a second.
Im for sure doing the wires first, i hate them though

Oh well, ill be thankful if its only the opti or wires.

Thanks for the help guys.

 

I'm not generally one to jump on "the opti is bad!!" bandwagon, but the symptoms sound like a bad opti.

 

If your Opti's optical sensor is bad, the PCM throws code 16 I think.

Check the fuel pressure too, if the pump is on its way out, itll run all retarded like that too. Happened to my mom's car once, just about the same description. If its not that, then its DEFINATLY something spark related ( Opti, coil, or wires )

 

Also the car seems to run alot worse the hotter it gets. Im thinking maybe wires because my friends did the same thing and all he had was a burnt #6

 

My optical disk was warped causing interference with the sensor and it didnt throw a code... Try things small, like the coil or coil wire

Though when my opti went out, i had the same symptons as you, and my opti only lasted 50k miles

 

It isn't the Opti, but it is the cap and rotor...IMO..70K on is alot of miles on any car. this is why I switched over the a Delteq unit. I have 130,000 on the clock with the orginal opti.

 

Yeah but any ideas why the heat is playing a huge role in the misssing?

I mean running around town today it got hot and started missing at idle


But when its cold its almost perfect.