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- - 95 z28 Intro (https://www.camaroz28.com/forums/new-member-introduction-118/95-z28-intro-886689/)

I’m a 22yr old college student who has a terminally ill mother. She was the one who found the car for me, $1500 garage kept and well looked after. The guy needed money because of a recent divorce. 109k on the odometer and after a grand total of ~$2500 it was mine and flying down backroads. I hope to keep this car a lifetime because, I know my mom won’t be around nearly as long as she deserves, and it might be one of the last big things she gets a chance to do for me.

The car runs like a dream 90% of the time and goes like crazy. The only identifiable mods it has is a CAI and a cat back Borla exhaust. Plus when I had codes ran at O’Reillys the guy said most the engines safety features had been turned off. I’m saving up money for headers at the moment and hope to turn it into a streetable 300-400rwhp dream. I enjoy taking it to the local car meets. It seems that the import guys are the most interested in the rumbling v8 fighter jet. I don’t know a ton about cars but, I keep oil changes up to date. I can’t afford a mechanic for anything so I keep my 98 k1500 and camaro on the road with a lot of research and a give it he** attitude.

Now for the bad. Any advice or trouble shooting tips would be greatly appreciated. When I most recently ran codes it came up with a Interrupted o2 signal. The issue the car is having is that it will begin to stutter after holding speed for a while. I can blip the gas and it’ll straighten out and the check engine light turns off until it decides to get funky again. A suspected vacuum leak, it idles a tad rough but not so bad that it’ll die out at a stop light. Then a small oil leak. My uncle who has been a mechanic for nearly 30 years suspects the back end of the intake manifold gasket. Sadly he lost his shop during his battle with cancer and I don’t like to rely solely on him for help because, I know he struggles sometimes. So I’m hoping that’s where this forum comes in.

Re: 95 z28 Intro

Welcome to CamaroZ28.com.

Looking over your post:

- I have no idea what the auto parts guy meant with his comment about “most the engines safety features had been turned off”. The PCM codes deal with emissions and the sensors and actuators that control the engine. The codes all have numbers that tell you the health of the sensors, etc., and how well the engine is running. Are you sure he didn't indicate the emissions systems had been turned off? Actually I'm surprised the parts store could even read the 1995’s OBD-1 PCM. Most shops see the 95’s 16-pin diagnostic connector, try to hook up an OBD-2 scanner, and get “unable to connect”.

- Does the car have the M6 (T56 6-speed manual) trans, or the A4 (4L60E 4-speed auto) trans? That affects trouble shooting.

- There is no diagnostic code for “Interrupted O2 signal”. Since there are multiple codes for each of the two O2 sensors, you need the exact numerical code (example - DTC 44) in order to determine the fault and the possible cause/fix. With the rough idle and the SES light coming on while cruising at steady speed, I'd suspect a problem with the EGR system, but that's a very preliminary guess.

- An oil leak at the back of the intake manifold, toward the passenger side is a VERY common problem with the LT1 engine. From the passenger side, take a paper towel, reach under the cowl to the back of the intake manifold. Wipe along the intake manifold/engine block. You'll find the oil if that's where the leak is. There is no manifold gasket at the back of the block. A bead of RTV is used to seal the joint, and dries out, causing the oil leak.

My suggestion would be:

- add a “signature” so everyone knows the specifics of your car:

https://www.camaroz28.com/forums/lt1...nature-879835/

- start a new thread in the “LT1 Based Engine Tech” forum, specific to the rough running/rough idle/code.

Here's a link from Shoebox for the codes specific to your 1995:

http://shbox.com/1/Dtcs.htm

While you're at it, check Shoebox's entire site - best reference site on the internet for LT1 engine info:

4th Gen LT1 F-Body Tech Aids

Re: 95 z28 Intro

Here's one of Shoebox's photos of the rear of the engine. Note the bead of copper RTV that has been squeezed out of the joint between the intake manifold and the block, when the manifold was tightened down. That's where you want too look for the oil leak.

http://shbox.com/1/egr1.jpg