So I just had my Ken Harrison cats and 02 sensors put on and my tune installed.
Before the tune I had an issue with the car bucking a little when I tried to accelerate and a little bit while I was at cruising speeds. It has gotten worse with the tune especially going from 1st to second gear. I have replaced the plugs and coil packs as well. What could be my issue?

 

How many miles? Any OBD codes? Any chance what you're feeling is traction control? Areas I would consider...

1. Fuel filter
2. Air filter

Good luck!

 

No codes. I don't think it's traction control. I replaced the air filters in April 2018.

 

Full disclosure - I haven't worked on my Aston, but I've done a lot of wrenching on 911 street and race cars for 15 years. So...might be a complete miss here.

If there are no codes, and if we can safely assume the ECU would know if there were a misfire, I would then switch to thinking about the driveline. I don't know if you have the sportshift or manual. Could it be clutch slippage or something binding in the system?

 

+1 to the clutch or you might want just to give it a fuel and injectors cleaning.

If you ever fill up ur car when your nearly at the bottom you will be surprised what could get in those fuel pipe lines and injectors.
Good luck

 

take the tune off and spend a couple hundred for a diagnostic...doesnt mean u have to get it fixed at the dealer...Just knowing is a bargain vs chasing your tail all over the place

 

Also noticed today that at idle the car shakes a tad here and there and the Rpms go up a couple of hundred rpms. This was also happening before the tune, plugs, coil packs, o2 sensors and cats.

 

I hope they are all emphasizing this to customers but typically, there's an expectation from Tuners (that sell DIY Kits) that cars are healthy before adding performance mods.

Did you expect this tune to solve your pre-existing conditions? Sounds like the car was in no condition to be tuned..."tuned up" maybe but not performance tuned.

 

Could be a thermostat issue? I had a Miata, of all things, that'd fluctuate at idle, eventually dipping almost to the point of stalling out (but not while under load, in that case). The coolant was circulating to the radiator too soon, before the engine reached operating temp.

Perhaps with the tune, your Vantage is running a bit hot? I know mine tends to, even before reflash. The car especially hates stop-&-go traffic (those hood vents actually are important), although weirdly enough it runs cool as a cucumber coming off a track session. Car likes to go fast..

My other thought is a misaligned driveshaft. The car I bought (an '07 4.3L with manual) had it's clutch replaced early on by the first owner, at like 10k miles, and I remember reading somewhere that early clutch wear might be due to the propshaft being slightly off..? Mine turned out to be just fine. I presume the first owner was just a bit of a clutch-rider.

Or...maybe an inconsistency with the throttle body, and/or fuel pump? Correct me if I mistake, but the throttle is electronic in the Vantage, no? I know my pedal got a touch more lively after tuneup, and shrunk that first half-inch of dead travel (which is good), but I could see some amount of uncommanded acceleration if your tune changed the throttle response dysfunctionally..

..but what you describe sounds more like it's coming from somewhere between clutch-transmission-differential-traction, to my amateur senses.

Good luck, and drive safely fast,

-N