I have had my 94 z28 for a little over a year now I am still a high school student and bought the car as something fun to work on the car isn't daily driven as I bought another car so that i didn't put access stress on it since it is older. it only has 112k on it and i recently had the injectors cleaned to correct the small stutter the car developed when you got on the gas to accelerate from a stop or avoid the skip shift at 45 about a day after that the stutter got worse the car began to start missing a lot more even at idle and suffers from extremely poor performance. I went through and redid all the plug wires only finding one that had the sheath melted on the exhaust manifold. The Car had after marked exhaust with no mufflers and a single cat, the drivers side pipe has a weak flow of exhaust through it while the other side is fairly strong. I was told that the Car could have a clogged Cat, due to the junk the injector cleaner burned out of the engine. I only use 90 or above octane in the car and use full synthetic 5w-30 oil i have previously considered switching to thicker oil all year round But have heard that it makes the engine run hotter. The worst thing I have heard that it could be is a lifter but the guy that told me that didn't spend any time with the car. It starts first try as fast as i would expect a 25 yr old car to start.

Any suggestions would be very helpful I love this car and hate to see it sit

 

Tyler

Hard to diagnose over the internet without more definitive source of problem.

There are software programs you can download along with buying a cable to plug in a laptop to see the data

EHACK or scan9495 are two I have heard of but never used since I have a 96 OBD2 car

This kind of software would greatly help narrow down what may be the cause of the problem. Even if you don't know what the data means you could at least post data and ask ?'s about it

Yeah a clogged CAT will make a car run like crap but other issues more likely the problem

IDK if your car (F-body) is "true" dual exhaust or a "Y" pipe into one pipe then into 2 tail pipes so feeling the exhaust may not reveal much if it is not a true dual exhaust

a few tools to have are a fuel pressure gauge to rule in/out a fuel issue

A IR temp gun you use on each header tube where it meets the head is helpful to determine if one cyl is unusually cool compared to others. That would mean that cyl is not firing so plug/wire or Opti would be suspect for that cyl.

 

Have you scanned the PCM for codes? Have you checked the fuel pressure? Good basic first steps. Additionally, there is free data logging software available that allows you to record the PCM codes, sensors and parametric value data. We can help you interpret the data.

https://www.camaroz28.com/forums/com...95-lt1-874306/

As far as your "aftermarket" exhaust, what does it consist of? With only one cat, sounds like you have headers to a Y-pipe to a single cat in the stock location. Is that correct? If so, with only a Y-pipe and a single cat, how did you determine the driver's side pipe has weak flow? A plugged cat is a possibility, but with a Y-pipe and the stock location single cat, it would affect both sides of the exhaust, not just one.

Unless you have a problem with oil consumption, or low oil pressure, use only 5W-30 or 10W-30 oil, as indicated in the Owner's Manual. Do not use heavier oil.

You can delete the "Skip Shift" feature by unplugging the skip shift solenoid connector on the driver's side of the transmission. It will set a code (DTC 84) but that one does not turn on the SES light and does not affect the way the engine runs. Put a 2,000 ohm resistor across the pins of the harness connector, and no code.