Friday, January 11, 2013

That pesky rough idle

The rough idle... who hasn't ever had a car rough idled, raise your hand! I bet none of you has, unless you never owned a car... A lot of times I get asked this by customers how to get rid of it. Well I've been successful some times, and sometimes I haven't. It all depends on the reason why your car is doing it to begin with.

So what do you do? This is my solution, which depending on your car and your luck, might work or not. You have to decide how much money you are willing to invest in this problem. There are a couple of things you can try so I am going to write a list from cheapest to most expensive and you can decide when to stop.
  1. Fuel additive: add this to your fuel when you fill up your tank to clean the tank and the lines. I recommend: Red Line 60103 SI-1 Fuel System Cleaner - 15 oz.
  2. Mass air flow sensor cleaner: take out your mass air flow sensor and spray it with this product, with time dirt accumulates in this sensor and this makes a difference most of the time. I recommend: CRC 05110 Mass Air Flow Sensor Cleaner - 11 Wt Oz.
  3. Throttle body cleaner: spray this on your throttle body and wipe it with a rag, this makes a difference if it's never been done. I recommend: CRC 05078 Throttle Body and Air-Intake Cleaner - 12 Wt Oz.
  4. Engine clean: add this to your engine and follow the instructions, you'd be amazed what this product can do, when you add the new oil I recomend Motul synthetic oil (check next step) I recommend: Motul Engine Clean 6.7 Ounces 817028
  5. Motul synthetic: you can try changing the oil with this expensive synthetic oil for big changes, I do it on all my customers car and I never had a problem and very drastic improvements over time (make sure you use the right spec for your car!). I recommend: 
  6. Motul X-clean 8100 5W30 Synthetic engine oil
These are the cheapest ones from a couple of dollars to a couple of hundred as you can see. I also recommend for you to change the air filter and the fuel filter for best results.

1 comment:

  1. Excellent article Daxter. For those who cannot obtain Red Line 60103 SL-1 Fuel System Cleaner, I would suggest adding a can of SeaFoam to a tank of high test gasoline. I used SeaFoam on all the motorcycles in my dealership to prevent and clean up fuel line problems, and the product improved performance of my X and S Type Jaguars.

    I am currently troubleshooting rough idle of my 2003 S-Type Jag and its looking like the cause is numerous vacuum leaks and the throttle body, typically isolated by a competent dealer performing "smoke injection testing" on the vacuum system. From that point on, its a matter of identifying vacuum leaks, and purchasing all repair parts that typically fail over time, including those that are hard to get to like plugs, coils and vacuum line elbow, well hidden beneath the upper intake manifold.