Q: Car running really rough

asked by on January 19, 2017

I own a Mazda Tribute. And it's been running on like 4 cylinders we've tested the coil packs and changed them and the same with spark plugs. We cannot seem to find the problem. It is automatic and it sounds like it wants to stall. Just won't idle. It stalled me the other day we've also checked the cat converter and that's fine.
My car has an automatic transmission.

Hi There, If you have tested and checked all coil packs and spark plugs with everything checking out properly, it may be likely that your issue is related to fuel delivery such as low fuel pressure or potentially a dirty or faulty idle control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. This is also an important function when starting the motor as it allows the motor to run and idle on it’s own once the motor fires. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed while adjusting the air/fuel ratio constantly to allow this to happen smoothly. When the engine RPM drops below the normal range of about ~800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.

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

Whenever the gears shift it jerks why

Hi John. Thanks for sending your question to us tonight. Quite often a clunking or jerking motion while shifting is typically an indication of a fluid obstruction in the hydraulic lines of the transmission. However, it can also be caused...

Why is my 2004 chevy malibu classic wont start in the morning when its cold/moist outside but when it gets hot my car will start

You may have spark plug wires that are arching to ground and when cold and damp the plugs needs extra power to jump plug gap and wires ground out first before spark gets to plugs. Try replacing plug wires and...

2000 Mercury Sable power steering leak

Hello, and thank you for writing in. The vehicle's in-line filter is housed in a unit that is either clamped on or has a quick disconnect. If you are able to locate the leak, you can determine if the filter...

Related articles

The Best Used Cars to Buy If You Just Retired
Here’s Here’s a cruel, hard fact – car manufacturers no longer target seniors. Instead, they devote their time and energy to appealing to the 18-45 demographic. Still, some features make certain cars more suitable for older drivers. We have...
A Buyer’s Guide to the 2012 Mazda MX-5 Miata
The The Miata is one of the few cars of the last few decades to become an instant – and enduring – classic. Adored among young and old, male and female alike, the car has maintained popularity as well as...
The Best Used Cars to Buy for Long Commutes
Most Most of us are faced with the prospect of commuting back and forth to work on a daily basis, but some have a much longer drive than others. When it comes time to buy a car, you need to...