Skip the auto shop - Our mechanics make house calls

Q: Rough idling misfire & a thumping sound from the front of engine

asked by on

I replaced the timing gear & chain on Land Rover discovery, oil pump & engine head.the vehicle still have a rough idling ,a flashing check engine light,misfire codes cyl 2&8 misfire,I took a vacuum test says late engine timing.Can this be a faulty cam position sensor?

My car has 128000 miles.
My car has an automatic transmission.

Hello. It sounds like your cam timing may still be off or there may be another issue. I would typically do a compression test first. If the compression is low on only a couple of cylinders, then you have an internal engine problem. If it was low on all cylinders, then you have a timing issue and need to recheck the recent work that was done. If the compression is fine, then you have another issue which may be related to ignition timing or you may simply have a coil or injector issue. These parts would have to be tested separately to isolate the cause of your rough idling issue. A thorough diagnosis of the Check Engine Light code and relevant systems will also help to pinpoint the problem.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Rough idling

Hello. This could be caused by a variety of things. It could be that your spark plugs or coil packs are misfiring. This means that the coil pack is not sending the proper electricity to the spark plug. It could...

Q: The sale ad says this: "Was rebuilt from top end. Lower end makes noise and won't engage." What does it mean in cost of repairs?

Hi...the most efficient thing to do is schedule a pre-purchase vehicle inspection at the conclusion of which you will have a much better idea of the total vehicle condition not just the engine. The ad language you are inquiring about...

Q: Car overheating, battery light on, and can't steer my wheel properly. 2001 Pontiac Grand Am

Hi there - your symptoms could indicate a failure of the serpentine belt - aka accessory belt - which drives the alternator, power steering and water pump. If the power steering pump seized or caused excessive drag on the belt,...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...