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Discussion Starter · #1 · (Edited)
I saw this in a closed thread and it mirrors everything that mine is doing. I'm at my wits end. There are no codes pending or history.

The Impala bucks and jerks on acceleration. It almost acts as though its starved for fuel (no power under load). If I keep the gas on while it's doing this it will buck and sputter and eventually stall. Won't pull itself up a hill from a dead stop, but can usually keep it moving forward on level ground by getting off the gas, and lightly back on the throttle. When it happens the Tach jumps around like a rabbit.

It idles great, starts every time, and it's not throwing any codes. Revs up when its in park with no sputtering or missing at all, it only happens under load. It happened last month and had to get it towed home. I thought I had it fixed after replacing the TPS, Idle Air valve, Fuel Pump new (within 1 yr) pcv valve, Trans rebuilt in January, temp sensor, and fuel pressure regulator. I put a new cam position sensor and plugs and wires. Fuel pressure is within specs. It ran fine for 350-400 miles. no codes at all to work with. Has anyone had or heard of a similar problem?
 

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Do you know the age of your catalytic converter? I don't want you to take it that is your problem, However I did have some of same type issues on my Regal that is also a 3800 like couple of my Impalas. After the Repair it is back to normal.

James
 

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Discussion Starter · #3 ·
I believe its an OE cat. I checked the back pressure and its relatively strong. But I cannot say it's not clogged. I checked it for rattle and vibration it doesn't even get a chance to warm up to do this though. I have posted a YouTube video of what it's doing because I'm that fed up lol. https://youtu.be/AGJQRQXvwMU

I don't know if that helps.
 
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