[St.Jimi]

Here's the story. I bought this car off of my buddy that I have known for years. He was going to scrap it for $200 so he agreed to sell it to me for $250.

Down to the meat and potatoes. The biggest problem with the car (other than the power steering is out, different post later) is, while driving, the car runs fine until I try to accelerate quickly. The engine sputters and loses power (doesn't die just runs especially rough) once I hit around 3,000 or 3,500 rpm. This makes overtaking vehicles and maintaining speed up hills rather difficult. It is also worth mentioning that at no time during a 20 minute drive did the check engine light come on or blink, even when the engine was actively sputtering around 3.5k rpm.

My friend who sold me the car says the spark plugs are relatively new and "shouldn't be the issue" but I also fixed the "broken" windshield wipers with a few ratchet turns so I'm not sure.
Assuming he is correct, I have a few ideas (coil packs? Incorrect spark plug measurements? Fuel injectors need replaced? Catalytic converter? MAP/MAF sensors?)
The exhaust system also needs repaired for sure, given that the mufflers are in the trunk, but while I'm sure that's not helping, I'm not sure it's the root cause of the engine acceleration stutter.

Has anyone else had a similar issue? I'm not sure if this issue would be particular to the L67 supercharged 3800 or not. Thanks for the help!

 

[dezldave961]

Clogged cat, coolant leaking into the intake, or the engine otherwise being restricted and most likely causing the engine to knock a lot and have to cut power. Pro-tip: if a car tells you it's not happy (sputtering, etc.), don't apply that stress to it until you can dig in to diagnose the issue, regardless of a dash light or not.

These have a very useful OBD2 system that you can plug into and monitor, either with a $15 ELM bluetooth scantool that connects to your phone, or something more expensive that basically does the same thing. I guarantee the symptoms will show themselves quickly if you monitor the computer to see what the spark, fuel, and underlying info is telling you.