Engine Misfire, Fixed When Car Restarted?

CanadaZ4M · 05-17-2021, 10:01 AM

Hey all, thanks in advance for the replies

The Car

2008 BMW Z4 M Series
60,000km
6-Speed Manual

Issue Key Points

- Misfire/Hiccup/Acceleration Cut Out
- Occurs when driving ~100kmph for a bit then once happens will occur at any speed driven.
- When Misfire/Hiccup occurs it feels like the throttle is cut in and out when the gas pedal is depressed but will not allow the car to accelerate or gain speed. Car will slowly drop in speed due to this.
- The problem is corrected when the car is turned off and restarted.

- No engine lights have come on during any of this

The Issue

Car is stored in a garage during winter and driven summer months. Started the car up yesterday fine and drives well without issue at lower speeds <60km.

When I was driving the car for a while (~20km) at highway speeds the car started to feel like it was misfiring (When I press on the gas pedal it feels like acceleration cuts in and out (misfire? Hiccup?) and would not allow me to go any faster and will slowly drop in speed due to this.)

When I shifted into lower gears/reduce to slower speeds it does the same thing. The thing is I pull over to the side of the road wait a bit then drive and it will drive fine for until I get past 50kmph or so and then the problem reoccurs.
Now the weird thing, when the car is turned off and then turned back on with no waiting it will drive fine again until I reach highway speeds and stay there. The car hasn't thrown any check engine lights or other lights on the instrument panel.

Steeler · 05-17-2021, 12:35 PM

Welcome to the forum.

I would scan for any codes and start there.

Sounds like limp mode but need to see any codes that are present to give an educated diagnosis.

Coi · 06-09-2021, 04:47 PM

On my E93 3 series I had similar symptoms when a coil pack was going out except there was a CEL. Whenever engine was under a decent amount of load (merging on to freeway, going uphill, or even just enthusiastic acceleration) I would get a misfire and a check engine light that would be cleared by pulling over and restarting the car. Swapped the coil pack in the cylinder indicated by the misfire code and it went away.

Not having any codes makes it harder to diagnose, but some ECUs do record number of detected misfires per cylinder even without CEL. Could help to pinpoint if it's a specific cylinder or not.

05-17-2021, 10:01 AM	#1
CanadaZ4M Registered 0 Rep 1 Posts Drives: 2008 BMW Z4 M Join Date: May 2021 Location: Canada iTrader: (0)	Engine Misfire, Fixed When Car Restarted? Hey all, thanks in advance for the replies The Car 2008 BMW Z4 M Series 60,000km 6-Speed Manual Issue Key Points - Misfire/Hiccup/Acceleration Cut Out - Occurs when driving ~100kmph for a bit then once happens will occur at any speed driven. - When Misfire/Hiccup occurs it feels like the throttle is cut in and out when the gas pedal is depressed but will not allow the car to accelerate or gain speed. Car will slowly drop in speed due to this. - The problem is corrected when the car is turned off and restarted. - No engine lights have come on during any of this The Issue Car is stored in a garage during winter and driven summer months. Started the car up yesterday fine and drives well without issue at lower speeds <60km. When I was driving the car for a while (~20km) at highway speeds the car started to feel like it was misfiring (When I press on the gas pedal it feels like acceleration cuts in and out (misfire? Hiccup?) and would not allow me to go any faster and will slowly drop in speed due to this.) When I shifted into lower gears/reduce to slower speeds it does the same thing. The thing is I pull over to the side of the road wait a bit then drive and it will drive fine for until I get past 50kmph or so and then the problem reoccurs. Now the weird thing, when the car is turned off and then turned back on with no waiting it will drive fine again until I reach highway speeds and stay there. The car hasn't thrown any check engine lights or other lights on the instrument panel.
	Appreciate 0 Tweet Quote

05-17-2021, 12:35 PM	#2
Steeler Colonel 2429 Rep 2,704 Posts Drives: Built not Bought 04 Z4 VF Join Date: Feb 2013 Location: Kitchener Ontario Canada iTrader: (2)	Welcome to the forum. I would scan for any codes and start there. Sounds like limp mode but need to see any codes that are present to give an educated diagnosis. __________________ W2A Intercooled Vortech V3Si, custom ducting, Alpha N, 60# Bosch,2.62 pulley, multi port WMI, Severn Tuning(pokeybritches), Tial, magnaflow,SS race muffler, 42 design,3.91LSD, H&R, Hotchkis,ST coils,Konis, Megan camber arms, AKG SS, Nylon mounts, Poly bushings, Carbon interior, CF Aero.APEX
	Appreciate 0 Quote

06-09-2021, 04:47 PM	#3
Coi First Lieutenant 289 Rep 323 Posts Drives: 21 X3 M40i, 07 Z4MR Join Date: Mar 2021 Location: Cal iTrader: (0)	On my E93 3 series I had similar symptoms when a coil pack was going out except there was a CEL. Whenever engine was under a decent amount of load (merging on to freeway, going uphill, or even just enthusiastic acceleration) I would get a misfire and a check engine light that would be cleared by pulling over and restarting the car. Swapped the coil pack in the cylinder indicated by the misfire code and it went away. Not having any codes makes it harder to diagnose, but some ECUs do record number of detected misfires per cylinder even without CEL. Could help to pinpoint if it's a specific cylinder or not.
	Appreciate 0 Quote