Q: Awful gas mileage, loud ticking, fluctuating RPMs, poor acceleration

asked by on March 19, 2018

2008 Chrysler Sebring convertible, 3.5l, 105k miles.

Prior to me replacing the intake manifold gasket and spark plugs, the car ran fine, but it did have a lifter tick that went away once the engine warmed up. After replacing those, the tick no longer goes away and the RPMs fluctuate slightly. I can not find a vacuum leak, I replaced the EGR valve gasket, MAP sensor and wires. It has no engine codes but the problem is still there along with god awful gas mileage, and accelerates poorly.

Any tips are highly appreciated.

My car has 105891 miles.
My car has an automatic transmission.

The RPM fluctuation, inconsistent idle, lack of acceleration, and poor fuel economy are all consistent with faults such as vacuum leaks, EGR system malfunctions, malfunctioning oxygen sensors, dirty fuel injectors, fuel pump malfunction, faulty spark plugs, a faulty mass airflow sensor, or a faulty throttle position sensor. An automotive scope can narrow the diagnostic. The root cause can be pinpointed, and the required repairs made, if you request an engine diagnostic. If you have further questions or concerns, do not hesitate to re-contact YourMechanic because we want you to make the most of your repair dollars and help you to get the best possible results.

Was this answer helpful?
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

Get a quote

What others are asking

Hi Jose

There are two camshaft position sensors on your vehicle, designated "left" and "right". In addition, there is a crankshaft position sensor. YourMechanic offers diagnostic and replacement services for these sensors. In the case of the camshaft position sensor, request CPS...

Oil sensor not working properly.

If the oil was checked first using the vehicle's computer and it read low you were correct to top it off. However, sometimes these vehicles can take a few minutes or a few miles of driving to reset the gauge...

Won't start won't lock

Hey there, thanks for writing in about your 2008 Lexus LS460. This sounds like it is caused by a dead battery. The battery will need to be charged to see if it will accept a charge and then load tested...

Related articles

How to Customize a Chrysler 300
The The Chrysler 300 is an extremely popular model of sedan with sleek styling reminiscent of more expensive brands like the Bentley at a far more affordable price. It’s a great long-distance cruiser with get-up-and-go, which inspires great loyalty to...
A Buyer’s Guide to the 2012 Chrysler 300
The The Chrysler 300 is a large luxury sedan that looks great, handles well, and has more power than many realize. Chrysler was once one of the biggest automakers in the world, and with this vehicle, they showed that they...
The Best Used Cars to Buy If You're a Rock Climber
If If you’re a rock climber, you want a vehicle that gets you where you need to go, even if the terrain gets rough. You may be living out of your vehicle at times, so you also want a rig...