About 2 weeks ago (after the car driving as good as ever) we parked it for the night. Everything was fine. The following morning we started it up to find heavy exhaust fumes and a rough idle. We took her out for a test drive to find we had virtually no power. The acceleration was gone, the RPM's didn't pass 2K even approaching 65MPH (which took a nice 30+ seconds to reach). Any time the gas pedal was more than barely depressed the engine produced a loud chugging/clicking sound and stopped accelerating (even though it was obvious it was trying to).

I have taken it to a few shops and this is what ensued.

Car is a 1996 3.8L V6 Camaro with 14X,XXX miles.
The car was coded with 'Random Multiple Misfires' (P0300). It never listed the misfires on a specific coil or part.

I was told by the mechanics at Tire Master that it was simply an issue of bad plugs and/or wires. I had the plugs replaced with Autolite Double Platinum plugs, as well as new plug wires. No difference at all. They then suggested it was the Ignition Control Module. This was replaced with no improvement.

At this point I took the car to another local shop where they did further testing. The mechanic first cleared the P0300 code and drove it around the block. He returned and pulled the codes to find another P0300 (shocking). He tested the first ignition coil (Marked 6 and 3) which came back fine. He replaced the EGR Valve with a new one for diagnostic purposes and took it for a drive. Still no improvement. He then noticed that the Catalytic Converter was glowing cherry red. He dropped the exhaust to bypass the converter and still had no improvement. He visually inspected the CatCon itself to find it was free of debris and obstruction or damage. He tested the MAF which came back just fine. He's tested the fuel pressure while idling and under load (35-45MPH). Both fell within range. This rules out a weak fuel-pump I believe.

So this brings me to a loss. What the heck is wrong with my Camaro?

Problems:
RPMs limited to 2K - 2.5K regardless of speed.
Heavy smell of exhaust and hot metal (from CatCon)
Virtually no acceleration. 20-30 seconds to reach 45MPH from standstill.
Rough idle that causes the car to shake.
Loss of gas efficiency.
Flashing CEL (Due to overheated CatCon I believe).

Parts Replaced:
6 Spark plugs and 6 Spark plug wires.
Ignition Control Module
Fuel Filter
Used fuel-treatment and injector cleaner.

Tested:
Plugs, wires
Ignition control Module
MAF Sensor
Catalytic Converter / Exhaust System
Fuel pressure / fuel pump
The first (6/3) Ignition coil pack

I'm unsure if he tested for vacuum leaks but I'll confirm this shortly.
Also, a few months ago we had a code for an O2 sensor. We were told it needed to be cleaned. This code stopped appearing long before the current issues began.

Note: He may have tested more but I haven't spoken to him in about an hour and a half. I'll find out what else he tested shortly.

*Update*
He has suggested it might be bad engine timing, a bad computer, or loss of compression in the engine. Regardless he is done trying to fix it. Looks like I'll have to find Mechanic# 3.

 

Quick update.

The mechanic just brought my car by. No vacuum leaks, and he tested the other two coils and plugs. The firing order is right and all the plugs are firing beautifully. At this point it is either an obscure mechanical issue or a wiring issue according to him. I doubt it is mechanical as the car ran perfect, then suddenly out of nowhere had an issue. Anyone would be hard-pressed to find a car that has jumped a tooth or something while it's parked in a driveway hah.

The new ignition control module is now coding, but the coils and plugs are all tested and working. The plugs all fire in the correct order. What are the odds that a new ICM would produce the -same- issues, no better no worse, as the old one and provide a code that the original did not. I'm so confused by all of this. I'm thinking perhaps the ignition wiring (perhaps to the actual module?) is faulty or damaged causing some issue with firing timing? Any input at all is appreciated.

 

Well, your engine is definitely running rich.
1) You can smell it.
2) The cat converter turning red is a "normal" reaction, because it's burning up the excess fuel.
Random misfire codes are probably one of the hardest ones to find an easy answer for, which is why you start throwing random parts at it.
Did the fuel pressure check out to be within specs?
Has the fuel pressure regulator been ruled out, and has the vacuum line to it been pulled off to see if there is any fuel inside the line (means it's bad) or to see if removing the vacuum source changes anything for better or worse?
You could also have leaking or malfunctioning fuel injector(s).
And has the mechanic checked for a good consistent spark at all the plugs?

 

The fuel pressure was within normal range (46-52 I think he said). The fuel pressure regulator tested fine. He said he checked for a vacuum leak but I didn't think about the fact that this does not entail checking the contents of the actual lines (such as fuel leaked into them). At one point he removed the EGR and tested the system for suction which was fine according to him. The second mechanic said the plugs were all firing perfectly.

My girlfriend just got back from driving the mechanic back to the shop. The car is worse off now than it was before. Now there are issues of backfiring before the car even hits its crippled RPM max of 2K. What would be the best way to check for fuel/foreign content in the vacuum system?

Also: I don't recall any mechanic mentioning the fuel injectors at any point. I assumed that since the fuel pressure was good while under load and idling that the injectors were fine. Is this something I can test at home? I've shelled out so much money that I'd prefer to do any basic testing and diagnostics at home.

Thanks for the response.

 

First you want to find out if your problem is too much fuel because of excessive flow, or because of it not getting burned up in the cylinder(s).
Checking each port at the exhaust manifold with one of these infrared thermometers: http://www.harborfreight.com/homepag...ter-96451.html could help to determine what's going on.

 

Many of the parts you mentioned that you had "tested" will pass most tests is they are failing randomly. A coil and a modual can pass every static "test" and still be the problem, only a a Scope will pick it up and that has to be hooked to the car while that failure is happening.
I am really not sure how far your going to get with any equipment unless you have a U-pull it with dirt cheap parts. Your best bet is to find a mechanic that knows GM FI and has the correct equipment that he does not have to guess. This might not be FI or ignition, timing chains normally jump either during deceleration or when the motor is shut off.

 

I just took it for a test drive to see how it ran first hand. Oddly enough it accelerated to 45MPH relatively fine minus a single backfire. However once I reached 45 the RPMs would reach 3K and bounce down to 2K and back repeatedly. I don't have the money for the laser thermometer right now sadly. A few others suggested perhaps a stretched/worn timing chain might cause a poor combination of air-to-fuel mixture. I have no idea of the validity of that idea, though.

My issue right now is that I can't really take the car far enough away to even get to an auto parts store, so I'm left with a set of sockets, a multimeter, and other hand tools to help find the issue. The car is overall worse having it checked out.

I'm still confused as to why the new ICM would be coding when the old one did not, given the zero change in performance since replacing it.

Anyone want to buy a 96 Camaro? She runs great

 

3.8? Is it a 5-speed or auto?

 

I just started the car, and barely poked the connector on the back of the ICM. The car sputtered and died. I'm hoping this is the issue as he didn't have much time to 'check the wiring'. Is this a good sign? lol

 

Pull the plug. Check for any corrosion, bent prongs, etc. Then put the plug on and off a few times to polish the connections.