Q: High RPM but Slow acceleration

asked by on August 16, 2017

First - car idles high at first start in the morning at 2000 rpm.

When I press gas pedal - RPM goes high but acceleration is very slow. I had RPM at 2 - 3rpm while it was still under 15 mph & slowly climbing.

It's not the transmission. I took a temp reading of CAT & at stayed around 250F front to back.

I had a YOURMECHANIC mechanic in person give me a diagnosis for other stuff and he suggested a tune-up. Car had a tune about a week ago - new spark plugs, wires, fuel injectors, IAC valve, MAF, fuel filter.

I'm thinking it's the CAT because it's 24 years old and prior to the tune-up it was misfiring and all the fuel was not burning. This may have caused an old CAT to get clogged up.

PLEASE - NO ambiguous answers.
Thank you.

My car has 177000 miles.
My car has an automatic transmission.

Hi Giovanni,

Thank you for contacting us. We understand that you think it’s the CAT. However, form our end we cannot state that with 100% certainty. Is it possible that a clogged up CAT is the source of the high RPM and slow acceleration but it would also be inaccurate to state with 100% certainty that your transmission is not the source of this problem - unless you have removed it, fully inspected the torque converter, each seal or gasket and hydraulic line.

In order to further assist you with your repair needs, we will need to have a mechanic to physically inspect your car to have it correctly diagnosed. After the mechanic completes the inspection, he will give you a quote for the recommended repairs.

Please give us a call at 1-800-701-6230 between 6am to 5pm Mon-Fri and 7am to 4pm Sat-Sun PST so we can help you with your quote and booking your appointment.

Best regards,

Erick YourMechanic Customer Service Team

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

How do I make a phone call with Bluetooth?
If your phone is Bluetooth (https://www.yourmechanic.com/article/5-essential-things-to-know-about-your-car-s-bluetooth) capable and it’s paired with your car’s audio system, you can use the hands-free system to accept or make phone calls. Here’s how to do it: Turn the ignition to on. Make sure your...
How much oil does the engine hold?
Knowing the amount of oil your engine holds is important even if you don’t do your own oil changes. If you drive a 4-cylinder Accord, your engine holds 4.2 quarts of oil (including the filter). If you drive a V6...
Sunroof is not closing
Hello, if you don't hear the motor even try to work, you may want to check the fuses. If you hear the motor and it moves in small increments, you may want to try closing the sunroof by activating the...
Poor acceleration
The engine is equipped with fuel injection and pumping the gas pedal may be an indication that the fuel pressure is lower than normal or that the throttle control valve is malfunctioning. I recommend having the computer scanned for codes...
brake are making a metal loud noise when I brake.
Hello. The price to replace all 4 rotors, calipers, and brake pads is very close to the price quoted when I used the estimating guide that I use for repairs. The calipers are listed at $246 each, rotors are about...
Car stopped in middle of highway - 2016 Fiat 500
Hello. This is a new problem and there seems to be no information on this issue yet for your vehicle. I suggest having the computer tested to see if codes were set and have them diagnosed. Contact your local dealer...
Should I undercoat a 2010 Ford Escape in good condition?
Hi, thanks for writing in. If you live in the north, then yes. You want to protect your car against rust as much as possible. Texas uses sand instead of salt for icy roads, but if you know your state...
Rough idle/Check Engine light/Cylinder # 2 misfre
Hello, thank you for writing in. The spark plugs may absolutely be the cause of your misfire (https://www.yourmechanic.com/services/engine-is-misfiring-inspection). Even if only one cylinder is registering a misfire at this time, you should replace all of them at the same time....
Can I replace the tps sensor in 2007 f150 with 5.4L 3v triton 8cy or do i have to replace the entire throttle body
Hi there. It is possible to only install the throttle position sensor on a 2007 Ford F150. The problem typically comes with programming it with a different throttle body; which is why the auto parts store recommended the throttle body...

Related articles

Saab Certified Pre-Owned (CPO) Car Program
Many Many drivers who are in the market for a used Saab vehicle want to consider a Certified Pre-Owned, or CPO, vehicle. CPO programs allow owners of used cars to drive with confidence, knowing that their vehicle has been inspected...
How to Get Saab Dealership Certified
Saab car dealerships offer automotive technician jobs to mechanics who are Saab certified through the GM Service Technical College.
Understanding the Saab Oil Life System and Service Indicator Lights
Car symbols, or dashboard lights, are a car service reminder. The Saab Oil Life System (OLS) indicates when and what service your car needs.