Hey everyone I’m on my last Hope here... I picked up a 2001 Camaro 3800 series 2 with a 5 speed manual that didn’t run very good from the start. Last owner could never figure out the problem. After going through his work he mixed up cylinder 2 and cylinder 5 wiring them up to the coils. Also the mass air flow sensor was shot. So here’s a list of new parts so far
Mass air flow sensor
Fuel pump he put in. Said it was an ls1 fuel pump because he wanted to supercharge someday. I did some research to find out they don’t seem much different?
Fuel pressure regulator
new orings on the injectors
new fuel filter
new air cleaner
new ICM
new plug wires, (tried 2 sets)
new ac Delco iridium plugs
Both new Bosch front 02 sensors
Each coil tested good on the primary and secondary.
Fuel pressure is steady 40 psi at idle and 50-52 psi at WOT (while missing)
Hooked it up to a snap on diagnostic computer and the Stft was around-6 to -8 idling which is very rich. But it idles pretty smooth engine doesn’t shake at all, and runs amazing under 1/4 throttle, and will rev fine. But anything past that and it just falls on it’s face. Any help will be appreciated!

 

How where the coils tested? A coil can test fine with a Ohms test but carbon track thru the outer shell. The best way to test spark beside a scope is a spark tester.
https://www.harborfreight.com/90-in-...ker-63593.html

ICM can also be a source or random miss fire.

If the spark looks going you will need to watch all the sensor data while the car is running and verify readings. Is the air temp right? is the MAP sensor right?
(you don't need a snap tool to read sensors. Amazon sells a OBD2 blue tooth reader for like $12 and there are free apps for your phone

How does the car run with the Mass air flow sensor unplugged?

Mass air flow connector are a pretty common failure point. You can shake it and see if the engine sound changes. If nothing else shows up might be worth it to replace that connector.

Good luck.

 

Coils where just ohm tested. I was going to check other data tomorrow with a different scan tool. ICM was replaced with no help to the problem. Mass airflow sensor was shot when I bought the car, it ran terrible with it bad. Tried 2 sensors with same results. I did unplug the air temp sensor but I never received a check engine light or any benefits. Only codes that keep popping up are p1153 and p1133 insufficient switching. It will run fine through all Rpms as long as you are easy on the throttle. Also I’ve noticed coasting in neutral the idle will surge up and down but soon as you come to a stop it clears up. Doesn’t matter if your hitting the brakes or just coasting it surges the same.

 

Try unplugging the MAF sensor. If it runs better all that tells use is the issue is in the fuel side not the ignition side. Since the MAF is a main sensor with it disconnected it PCM will ignore most sensor data and run on a predefined fuel map.

 

Last Night I pulled the injector rail up a little and checked to make sure I didn’t have a leaky injector, while I was putting it back together I noticed I had #2 and #5 wires mixed up. Since there on the same coil You didn’t even notice a miss at idle. It seems a tiny bit better it doesn’t chug now it just sound as if the choke is on but it will rev fine all the way to 6k as long as you don’t put your foot in it hard. So the StFt is more than likely inaccurate since I think it was hooked up like that when I took it there.🤬🤬 I’ve only had the wires off about 15 times now and must have messed it up when I swapped back to the stock ICM. It has an idle surge now when your coasting tho. It will fluctuate between 1100- 700 rpms but stops soon as you come to a stop. I Unplugged the MAF and it runs exactly the same. Waiting till orileys opens to use there scanner and see if the StFt changed. But the surge sounds just like a vac leak surge but I don’t understand why it only does when I’m coasting. It does it a little when it’s cold but then goes away.. I think it’s making me crazy 🤯🤯

 

I noticed MAP seemed low at idle
I tried unplugging the MAF and there was no change. But I did notice the MAP was very dirty when I took it out so I cleaned it but never replaced it.

 

Your vacuum is reading to low to being at idle. I would verify that with a vacuum gage, The MAP sensor itself could be fine but something else could be causing the issue. If you check the vacuum the the meter reads 12 HP but the hand help gage reads18 they you could have a problem with the map sensor.