Q: Rough idling, hard shifting and shuddering at the highway

asked by on August 09, 2016

I bought a previously owned car, which has some issues both while idling and driving. When the vehicle is not moving, like at the traffic light, it idles very roughly. Also, it is very hard to shift gears while I'm driving on the highway. The hard shifting is accompanied with shuddering and chirping sounds. What should I do?

Car idle is rough Inspection $94.99 - $114.99 Get a Quote
Car is hard to shift Inspection $94.99 - $114.99 Get a Quote

Thanks for writing in about your 2002 Isuzu Trooper. The rough idle may be due to the fuel injection system being dirty or having an engine vacuum leak causing a lean condition. The hard shifting and shuttering with the chirping sounds like you have an automatic transmission lock up converter problem and should have the transmission checked. I recommend having a transmission expert inspect your rough idling and hard shifting issue in order to make the correct repairs for this scenario.

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 program MyKey?
The MyKey feature can be programmed to restrict certain driving functions. Functions like max speed max volume promote safe driving. To program MyKey. Press the Setup button until you see “Reset for MyKey Settings.” Press the Reset button. Press the...
Engine temperature keeps going up
Hello. The cooling system is designed to keep the engine at operating temperature. Hot coolant from the engine flows through the radiator, which lowers the temperature. The lower temperature coolant is then returned to the engine. The primary cooling system...
I had a p0405 get code replaced egr valve, map sensor,mad sensor, and PCv valve just to be safe but still getting the code why?
The code P0405 (https://www.yourmechanic.com/article/p0405-obd-ii-trouble-code-exhaust-gas-recirculation-sensor-circuit-a-low-by-jay-safford) and a rough idle is most likely due to carbon getting into the EGR pintle. This will hold the EGR open. When you are getting the rough idle you should shut off engine and remove EGR...
Vehicle won't start, once it's jump started it only stays running until you turn it off, then it work start again without jumping.
Hi there. There could be two problems here. It is possible that your battery is bad and will not take a charge from your alternator while driving. In that case every time you shut your car off you will not...
Steering issues, my car does not turn well
The power steering system may have a leaking return hose from the steering rack and pinion to the return reservoir. This leak can cause the power steering pump to suck in air into the steering system and cause noise and...
Ticking and knocking sound and follows as the rpm's increase.
I would have to listen to the noise firsthand to know for certain. However, one guess is that the noise you're hearing is from the valvetrain. Valvetrain noise, such as worn lifters or misadjusted valve clearance, is generally characterized by...
My air conditioner is not working , but my heater is , what can be the problem
Hello. Thank you for writing in. The A/C (https://www.yourmechanic.com/services/heating-ac-inspection) system and the heating system have relatively little to do with each other. They share a blower motor, and climate control switches. With the heater working we can assume that these...
My brake lights are not working, fuses are good
It is possible both bulbs are burned out. The filament in each bulb should be tested with an ohmmeter. The bulbs can also be powered off the car to see if both filaments work but be wary of short circuits...
Car cabin smells of AC refrigerant at times and now the AC is not cooling after about a month of filling it .
If you have detected a refrigerant and oil mist in the cabin, then an evaporator "area" leak is likely. However, any time there is one leak, the entire system should be pressurized (whether pre or post repair) and tested for...

Related articles

How a Manual Transmission Works
A A manual transmission helps a vehicle achieve a desired speed through the use of gears, a clutch, and a shifter. It works like this: when the driver wants to shift gears, he or she pushes in the clutch pedal...
The Importance of Warming Your Car Before Driving
Scandphoto / Shutterstock.com Many people feel that it’s important to warm a vehicle up before driving off. This has long been the dominant school of thought, dating from when cars had carburetors and many would not run...
Symptoms of a Bad or Failing Shift Selector Cable
Common signs include the indicator not matching the gear and the vehicle not turning off, starting in another gear, or not going into gear at all.