Skip the auto shop - Our mechanics make house calls

Q: my truck suddenly dropped to the four cylinder mode and is stuck there. Surely this is not normal. Is there any repair or fix?

asked by on

While driving slowly with a small load on a gravel road the truck suddenly lost power and died. It finally restarted but only runs on four cylinders now. It will not switch back to eight no matter the speed or load. What do I do?

My car has 230000 miles.
My car has an automatic transmission.

This sounds like a computer issue of some kind. Unfortunately, high tech scan tools may be necessary to diagnose this issue. I would recommend visiting your local dealership as they usually possess these tools. It is very likely that the powertrain control module could be malfunctioning and may require replacement in order to resolve this issue.

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!
  1. Home
  2. Questions
  3. my truck suddenly dropped to the four cylinder mode and is stuck there. Surely this is not normal. Is there any repair or fix?

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: Truck misfires when the engine warms up - 1995 Chevrolet C3500

If the heat sensitivity is a good clue, this could well be the ignition control module, which is quite heat sensitive on the big block Chevy's. Would check fuel pressure (while running) as well to make sure you're getting enough...

Q: weird engine noise

Hello. Though this can be caused by a transmission failure, most of the time it is either caused by a cracked flywheel or a failing timing chain. I usually try to narrow down the location of the noise as that...

Q: Is it possible that an aftermarket seat warmer could case a BCM to short out?

There is not enough information to go on to know if the aftermarket seat warmer caused a computer short. If you plugged into the power port and if system was overloaded then it should have just blown a fuse and...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...