Jerky on 1st and 2nd when cruising

[Fiat500USA]

I cruised around at 3,000 rpm in second gear and it was smooth. The other day I had an issue with some brief bucking when taking off but I attributed that to being low on gas and parked on a hill all day when I took off. It took me by surprise, so I guess Ill keep an eye on it, It was more like a flat spot in engine response, but the engine was cold and I didn't warm up and I did take off kind of fast while turning and going up a steep hill.

[Milnoc]

Just did the oil change. So much fun on this car with the awkwardly placed cartridge and drain plug!

I checked what I could. CV axles, bearings, bushings, and suspension are all good. I couldn't check the clutch, but there were no leaks at the transmission's fill and drain plugs or anywhere else. Also, the engine oil was still clean after almost 8,000 km. This engine is in really great shape!

The only explanation I can find is that I've only started daily driving my Abarth for my new job, and my ride home hits a traffic tie-up that forces me down to second gear where I now regularly hit its "jerky" spot.

I'll just have to live with its quirks. It's still the most fun I've ever gotten out of a car!

[Fiat500USA]

Just did the oil change. So much fun on this car with the awkwardly placed cartridge and drain plug!

I checked what I could. CV axles, bearings, bushings, and suspension are all good. I couldn't check the clutch, but there were no leaks at the transmission's fill and drain plugs or anywhere else. Also, the engine oil was still clean after almost 8,000 km. This engine is in really great shape!

The only explanation I can find is that I've only started daily driving my Abarth for my new job, and my ride home hits a traffic tie-up that forces me down to second gear where I now regularly hit its "jerky" spot.

I'll just have to live with its quirks. It's still the most fun I've ever gotten out of a car!

They are a lot of fun. I think of them as a 4-wheel motorcycle. Makes the daily commute a little more fun, plus you don't have to worry about the rain.

If you are looking to do something on the car, changing the spark plugs isn't a bad idea. The older cars change interval was around 30K miles, and that was extended on the newer cars, but it can't hurt to change them a little sooner as the plugs do deteriorate. Why drive around for the next 10-20K miles on sub-optimum parts, right? If they are the original plugs you may pick up some smoothness, plus you can check the PCV o-ring for leaks or change it as that likely will eventually happen.

The plugs are easy., Just be careful removing the coil connectors. We have a bunch of posts on changing plugs and the PCV Oring.

Here are some interesting threads tagged:
spark plugs
PCV Valve O-Ring

Have fun and keep us in the loop.

[lammie200]

Both cars that I have had (previous Sport and current Abarth) were prone to surging. Everything I did to them made the surging go away. Since we are talking Abarth, the 4c coils and correctly gapped spark plugs helped. A tune helped. A Forge recirculating blow off valve helped and also eliminated boost dumping. That is something the stock BOV and the Go Fast Bits BOV didn't do. I would start with the 4c coil packs and spark plugs and see where that takes you. Also, I would get the Alfa 4c coil packs and not anyone else's rendition of them. I have had zero issues with the Alfa's and have read how people have had issues with the others. My 2 cents.

[Milnoc]

I already changed the spark plugs some 10,000 km ago. I didn't feel any difference. Here's a picture of the old spark plugs. Left=passenger side, right=driver side. Replaced with the exact same brand and model, and were already set to the correct gap out of the box. I'll only replace the coils when I start to experience misfires. I've yet to experience any engine codes whatsoever.

IMG_20210725_220624_0~2.jpg

[map]

That's a nice color for the plugs. I wonder if the Abarth continued to use the standard plugs through 2019. The later 500 went to 100K miles between plug replacement but the manual shows 30K (48K km) for the 2018 Abarth.

Do I understand correctly, you get the jerking only when cruising above 3000 RPM in first and second gear? I can't say that I've felt anything like that in my '18 Pop. Then again, I don't usually cruise around town at that high an RPM. (I prefer seeing the guess-o-meter hover around 60 MPG, in town.)

[Milnoc]

No, it's well below 3,000 RPM, closer to 1,500-2,000 RPM. If I go below 1,500, I risk lugging and possibly stalling the engine. I only do 3,000 and above on a consistent basis on highways at 4th and 5th gear. In the city, I aim for 2,500 RPM and third gear.

[Milnoc]

I think I know what's happening. I believe my clutch plate may be contaminated by moisture. I had a jerky start this morning and I actually made the clutch play a tune while turning a corner after work.

The temperature in Ottawa has been extreme on a daily basis lately. At night, it can get cold enough for Environment Canada to announce frost advisories. In the morning, there could be a heavy build-up of condensation on the flywheel causing all kinds of havoc. Even during the day, it can get cold enough to screw around with the clutch as things get cold again.

Once the nights are warm again, I'll pay attention to any changes in the clutch's behaviour. I definitely don't think the clutch is slipping from excess wear because there aren't any sudden engine RPM increases whenever I accelerate with the clutch fully engaged. And if I don't rev match properly and release the clutch too fast, I can both hear and feel it right away. I might just need to wait until the moisture on the clutch has boiled off and doesn't reappear for a while for things to return back to normal.

I might go ahead and change the coil packs now to see if that helps with the jerkiness when coasting on first or second. It's a cheap and easy fix to try out.

[Milnoc]

Ordered Bosch coil packs part #0221504709 from RockAuto. Some preventative maintenance. The original coil packs are 9 years old.

The clutch was very smooth today. Seems like the moisture has finally boiled away. Still need to check the motor mounts.