# Sustained Loss of Acceleration and EPC Light



## KurtCav (May 8, 2010)

Today I was accelerating onto the highway and I got a weird error on the dash. It said "Max Engine Speed 4000 RPM", the EPC light came on, and the engine felt like it fell flat on it's face. It would not accelerate, only maintain speed at best. Almost like a limp mode. The car was vibrating a bit, similar to a misfiring cylinder but not quite. I pulled over, stopped the car, then started it again and it was fine.

Has anyone experienced this?

Thanks!


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## Ub3rN3rd (Feb 3, 2004)

Honestly it’s common issue. Take it to the dealer there is a quite fixes the dealers are doing. 


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## Zabes64 (Aug 29, 2018)

Run a scan, you likely had a cylinder or 2 misfire. Same thing happened to my 2020 on the highway.


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## VolksBerry (Dec 2, 2019)

This happened to me twice, usually when it was raining. Its an fault with the coil packs. The dealer swaps them around to find the faulty connection. If it happens again, select a lower gear to bring the RPM's up, the vibration will be more manageable. You at least be able to drive on 3 cylinders to get to safety.


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## RWBJettas (Nov 26, 2016)

KurtCav said:


> Today I was accelerating onto the highway and I got a weird error on the dash. It said "Max Engine Speed 4000 RPM", the EPC light came on, and the engine felt like it fell flat on it's face. It would not accelerate, only maintain speed at best. Almost like a limp mode. The car was vibrating a bit, similar to a misfiring cylinder but not quite. I pulled over, stopped the car, then started it again and it was fine.
> 
> Has anyone experienced this?
> 
> Thanks!


Just had the same problem on my 2018. The problem was the injector harness. Replaced under warranty.


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## KurtCav (May 8, 2010)

Scanned it and sure enough, misfire on cylinder 3 due to injector wiring harness fault.

Called the service manager and they're gonna take a look at it. Hoping they actually do something about it. Was sure to save the log.

Thanks for the help!


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## TigR (Jun 29, 2020)

Had the same issue in my 2020 R-line SEL took it to the dealer. Turns out had a faulty fuel pump 


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## KurtCav (May 8, 2010)

Wanted to follow up in this.

It took almost a month to get into the dealer. We ended up seeing the message on the dash again about a week later. On pretty much every drive you could feel the car hesitate every so often while cruising. Not a full blown misfire with a flashlight but close to it.

The dealer verified the fuel injector wiring harness was the issue by measuring the resistance then replaced it under warranty.

Thanks for all the advice.


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## gerardrjj (Sep 4, 2014)

Just had to replace my injector harness for EPC and limited power. Injector 3 intermittent implausible signal


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## Passatsquared (Oct 26, 2014)

I had this issue. It was 2 pronged for me.

Dirty maf sensor solved the limited revs and poor acceleration, but I still had a stutter, like I hot a dip in the road. It was like a dull thud. 

This was solved by the harness fix at the dealer. 

Clean those airflow sensors!


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