Q: The rpm jumps up and down about 300 rpm when accelerator is constant. Only seems to happen when traveling between 40-50 mph

asked by on April 21, 2017

The rpm jumps up and down about 300 rpm when accelerator is constant. Only seems to happen when traveling between 40-50 mph. Alternator, belt and tensioner was replaced at about 145000. Spark plugs were replaced at about 120000 miles. Air filter is clean and all fluids are new or full. There are no noises or smells.

My car has 148000 miles.
My car has an automatic transmission.

Loss of power Inspection $94.99 - $114.99 Get a Quote

Hello, thank you for writing in. The truck may be having issues with air sensors, fuel pressure, or other electronic issues. I have have to replace the fuel module and the mass airflow on my 1998 S10 with 168,000 miles. Fuel pressure can be tested in several ways, and you may want to start there. You should also have the truck scanned for diagnostic codes at your local parts store or by a technician. Even without a check engine light, there may be codes that indicate a component is about to fail. If none of the above is to blame, look into your gas recirculation system. For more help with diagnostics, contact our service department to schedule an appointment.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

What does the Brake light on the dash mean in a 2012 Toyota RAV4?
Your car is equipped with a number of important warning lights. The Brake light is there to warn you of a potential problem with the brake system. There are a couple of reasons that this light may come on: The...
Car not getting fuel
Not enough fuel at start up can be a possibility. This could be caused by damaged fuel lines, failing fuel pump, or even a clogged fuel filter or clogged injectors. The vehicle also won't start if there isn't enough air...
Car not moving when in gear
If the shifter linkage has failed or broke it will not allow the transmission to be put into gear. The transmission has multiple clutch packs that control the different gears that are used while driving. Inside these clutch packs are...
rough shifting high idle
Hello. This can be caused by a few different things. Most of the time it is caused by the needs for a tune-up (https://www.yourmechanic.com/services/tune-up) or a fuel system problem. Both of these will cause the car to run this way....
Is a leaky brake booster unsafe if fluid level is o.k.?
If your brake booster is leaking but your brake fluid level is full, your brake booster would be leaking vacuum. This would mean that your booster has a crack, the check valve is bad, or the hose that connects to...
My car tries to crank but won't start. It sounds like it is not getting gas - 2011 Jeep Grand Cherokee
Hi there. It sounds like it has a bad electronic ignition switch. I have seen a lot of these fail on this vehicle. I usually do a voltage test of the switch, but most of the time it is the...
i would like to know if i can do oil changes for other people and not be a qualified mechanic
Hi there. Changing oil, oil filters and air filters is typically a job that an average or non-professionally trained or certified mechanic can complete. It really depends on your comfort level, tools and accessibility to appropriate disposal methods (as oil...
Can i turn off the anti theft system of my 2014 toyota tundra
Hi Gigi. Unfortunately, there is not a manual way to deactivate the security system on your Toyota Tundra. It requires a software patch or removal - that can only be completed by the dealership. However, the reason your car will...
Check engine light after throttle body but had no head gasket 1994 Dodge Ram
Hello. I would need to scan the computer for codes to see why the light is coming on. After a head gasket replacement it may just be that something was left loose or not properly connected. If you want to...

Related articles

The Best Used Cars to Buy If You’re a Painter
If If you’re a painter, and you work for someone else, chances are you don’t care all that much about what you drive, as long as it gets you to and from work reliably. On the other hand, if you...
Chevrolet Certified Pre-Owned (CPO) Car Program
Drivers Drivers who are in the market for a used Chevrolet vehicle may want to check out cars under their certified pre-owned program. Many manufacturers have a certified pre-owned (CPO) program, and each one is set up differently. Read on...
How to Get Chevrolet Dealership Certified
Chevrolet car dealerships offer automotive technician jobs to mechanics who are certified through the many training programs available.