Problem description:

When i go over 75-80 my check engine light starts to flash, then if I let go of the gas pedal it becomes solid and stays of for about 80-100 miles before it resets the light. I feel like i have a good amount of power loss in the car and I can barely get up hills if I'm like not already going around 70 mph. So I was driving up a hill today and the check gauges light got on instead of the check engine light and my car was leaking some coolant. Another thing I have noticed is that when I am going around 50-60 mph and I push the gas pedal pretty hard the car starts shaking and kind of choking and the car doesn't accelerate, looks like a lots of problems at the same time oh and i took my car to the shop for a free trouble code check but there seems to be a electrical problem in my car and the trouble codes cant be read. so I have no idea what next educated step would be?

Car description:

Stock 3.8 V6 Camaro -99
115k miles

Thoughts:

Rattling exhaust system has a crack somewhere before cat that causes low backpressure?

bad coil packs?

Transmission going bad?

no idea really...

 

Try taking it to your local auto parts store and have them scan the codes for you.

 

I'd say you have a dirty maf. Buy some maf cleaner and try cleaning it. Back pressure should be less then 1 psi. The rattle from the exhaust is most likely at the joint behind the cat beside the drive shaft. When was the last time the spark plugs and wires replaced?

 

The flashing Check Engine light indicates misfire, severe enough to damage the cat.

The Check Gages lamp means just that. Did you check the gages? Being that coolant was leaking, I suspect the engine was overheating.

Shaking under heavy load, like going up a hill, is also an indication of misfire.

Don't get concerned about lack of back pressure, it won't cause misfire.

Get the PCM scanned by some one that knows what they are doing. If the CEL is off there should be retained codes from when it was on. As others mentioned, when were the spark plugs and wires last changed?

 

Spark plugs and wires were changed about a year ago, Im going to clean the maf and see if that helps.

In regards of getting the pcm codes checked is this done with a obd-II scanner? because for some reason when i took it to the shop they did not get any power to their scanner and could not pull any codes from my car. and i actually tried to take it to 2 different places and got the same answer.

could the misfire be from damaged coil packs or melted wires maybe?

 

Both old worn out coils or melted wires will cause misfire. Check over your wires and if the look good then it's either bad plugs or coils. You need a obd 2 scanner to check codes. The key also needs to be in the on position.

 

You more than likely have a blown fuse. The ALDL port usually gets power from the cigarette lighter/power outlet circuit. No power, and a scanner can't communicate with the computer. Might as well check all your fuses while you're at it.

 

I also have a 99 3.8 and I was having a similar problem with the shaking and flashing check engine light. i was getting a random cylinder misfire caused by a bad ICM (Ignition control module). the ICM is the electronic version of a distributor. Its very easy to remove and test at an auto parts store. you'll need to remove the (2) 1/2" nuts holding it to the engine (top). one 1/2" bolt (front), one 7mm bolt to disconnect the wire harness in the back. and a 7/16" to remove the 3 coil packs on top. call your auto parts store and make sure they have the right testing unit for the 99 camaro. some places have a tester but it doesn't work for the 99 Camaro. you'll notice when you remove the ICM from the heat sink that there is some dried up white paste between them. this is thermal paste. its very important to replace this with new thermal paste before reinstalling the ICM to the heat sink. If you don't you could fry the ICM $130.00-200.00 replacement vs. $1.50 for paste sold at all auto parts stores in those little packets at the register (ICM might come with a small pouch of thermal grease but its usually not enough for a good coat. you don't need much but enough to get good contact between the surfaces. make sure you get the old paste off before adding new (try using a small wire brush or scrubby pad). if you have a bad ICM i recommend getting a higher quality one with a lifetime warranty because i went through 3 cheap ones before getting a good one that didn't burn out in 3 months. you may ask yourself how i know so much about this well the answer is this this was a chronic problem for my Camaro that sucked the performance and economy out of my ride for about a year. everyone kept telling me it was the Cat, or spark plugs, or wires, or Coil packs but it was the ICM. good luck