Lgraz5

My car is a C230K, 2003, 230K miles, all original including battery, alternator, spark plugs, fuel pump, etc. It has been running rough at high speed, especially when accelerating, mileage off about 4 - 5 mpg but no CEL or loss of power. Smooths out a little bit after 50 miles of sustained highway driving but mileage doesn't improve. Recently I ran a bottle of Techron through it with no positive benefit, in fact, the problem seemed to get worse. But...300 miles after the Techron treated tank of gas, the problem abruptly disappeared! Like turning off a switch - engine smoothed out completely, MPG improved from 31 to 36.5 in less than 100 miles. Typical behavior for Techron treatment or something else going on? All thoughts appreciated.

phister

it cleans up the fuel system so your injectors, pumps, and lines probably got clean and got ride of all the gunk that what hindering the fuel system. but with that much mileage you should change out the fuel filter, spark plugs, and battery. all replace your air filter and cabin if you havent. the spark plugs should have been replaced at 100k according to the manual.

TexFinn

Spark plugs w/230K miles on them??? Damn!

Crna Mechka

Would be interesting if it really is the Techron that "flipped the switch".

What I'm asking myself is how do you get 36.5mpg - must be all highway I assume?

I used to get around 27mpg when I replaced the fuel filter and air filter a couple of years ago, but have not been able to get better than 24 lately. Could a treatment of Techron really bring back some of those lost miles?

Lgraz5

Yes, virtually all highway miles. Car consistently got 35 - 37 MPG until the recent troubles, that's why plugs, etc. have never been replaced.

kluvsbenz

Seriously?!! 230k miles on the plugs? I thought I was bad going over 100k on mine before I changed them Better change those plugs soon.

Lgraz5

If it ain't broke, don't fix it!

mitviet

Since we are on the subject, do you guys think I should use Techron on my '06 even though it has only less than 7K miles? given that it is 7 years old. I bought it in early Jan when it had even less than 5K miles.

Glyn M Ruck

Plugs over 100K places ignition system & coils under severe pressure that can lead to failure. Please change them.

You obviously had dirty injectors for Techron to work that quickly. It is more than capable of that. Valve tulips take longer to clean.

TexFinn

Haha... Same analogy could be used for example oil changes. You do change your oil, don't you?

phister

sounds like a person who doesnt take pride in keeping a car well maintained. shoot you can drive one tires till they finally fall off but you dont do that do you. you cant have that outlook on a car or it'll eventually lead to worse damage as glyn said. you really cant shell out 50-75 dollars for some plugs.

phister

i would use the techron every 3month or 3-5k miles even if it has that low miles. make sure its the chevron techron not the cheaper brand one.

Lgraz5

Nice! I have 230k miles of trouble-free driving on my car and I have to listen to ****? I don't think so.

WaveyKat

I wanna see a picture of the Cluster saying 230k :-)

sammydragon3

if u had that car since brand new. and show the od. i can sort of believe it. but very odd

if this is true then thats german quality

kluvsbenz

Sure Even a novice like myself can see what you are doing is wrong Maybe you already changed the plugs and you're not telling us

Crna Mechka

Nice. Going to grab a bottle at Advance Auto Parts later today. $6.50 with in-store pickup for those of you who are interested.

Lgraz5

Here's a pic of the MFD, taken today. Why do you doubt?

Lgraz5

So, do I win the high mileage award or what?

sammydragon3

wat were ur oil change intervals?

Lgraz5

Approx. 10K miles, more or less. Whatever the Service counter says.

sammydragon3

so u drove 23k miles a year for 10 years striaght?

and u owned the car since new?

Lgraz5

Bought it new in May 2003. From 2004 to 2010 I had an 80 mile daily commute, plus very frequent 500 mile weekend round trips. Recently my driving is down to 2 to 4 weekend round trips (500 miles) per month.

sammydragon3

this is the question that will hit the nail on the head

have u replaced your front end balljoints?

Lgraz5

Nope