surging - feels like a clogged fuel filter...

[kemerick]

I have a stock 2004 Mazda 6 3.0 with an issue that just popped up the other day. It has 70,000 miles on it and all I have ever done to it is change the air filter twice and do Mobil1 every 5k.

The surging of the engine only happens when I accelerate faster than a normal rate. That sounds funny but if I take off normally and then accelerate a little more it surges. If I take off normally and then give it a little more... it then surges.

If I put the clutch in, you cannot feel the surge. So it appears to be only when the car is under load. The surging is like the car is not getting spark or fuel and then all of a sudden it is. It kind feels like when the anti-skid thing kicks in and curbs the throttle.

I assumed it was the fuel filter and after calling the dealer and two parts places, they all said my model of car does not have one. So what else could this be? I am handy, would like to fix it myself and would like to avoid expensive trips to the dealer.

 

[RevLimitLaunch]

i'm guessing no CEL on huh? do a tune up on it lately? i doubt those parts would be the problem but i guess you'd kill two birds with one stone.

 

[kemerick]

i'm guessing no CEL on huh? do a tune up on it lately? i doubt those parts would be the problem but i guess you'd kill two birds with one stone.

No CEL and no to the tune up. All I have done is oil changes and two air filters in 70k. I guess I'll take it to the dealer and pay the $75 for the diagnotics or whaterver it costs.

Thanks for the respone and I'll re-post when I find out whatever it is...

 

[kemerick]

...that is unless you or someone else has other suggestions?

 

[Raynman]

I suspect your throttle body is starting to die.

Here's the symptom a fellow member experienced:

You will know because the car will shake and shutter like if the engine isn't getting enough oxygen. The engine light will light up and the car would not go above 30 mph. Once you pulled over or stop, turn off the ignition and on again, the vehicle will drive like the problem never happened except you will get a CEL. The CEL will disappeared after 4-5 starts but the code will be retained in the computer. So if you use a scan tool, you will access the code until it get erased. It happens to some vehicles but not others. This is a "gremlin" problem that is happening to way too many Mazda 6s(V6). I personally believe the problem is caused by the gear material being used on the throttle body. The problem only occurs, if ever, after 7000 miles or less. The gears either gets stripped by that point or it won't. Mazda dealers have been replacing the throttle body with a new one once this problem occurs but has never admitted to a faulty part. This bulletin is the 1st time they admitted to a faulty part on pages 2 and 3. Notice the quotes on page 3 where it says "BB" marking = Good part.

Please see the attached related TSB.

I'm guessing you're out of warranty, so you'd have to pay for the stock BB throttle body (if that is indeed the root cause).

Or, an even better alternative would be to purchase an optimized TB from Cordova Motorsports. I figure if you're going to end up replacing the TB anyways, might as well do an upgrade.

 

[kemerick]

The car is still under warranty but since I did not keep my reciepts for my oil changes, the extended warranty its essentially void. I'll take it in so they can tell me whats up.

The weird thing is, I can easily get it up to freeway plus speed, but I cannot do it quickly. I step on the gas and as I increase in speed I can increase the throttle all the way through the gears. The only time the engine appears to stumble is when I press harder. As soon as I back off a tad it goes away.

For sure... if its bunk I will be getting a better one. I have got larger throttle bodies for previous vehicles and it always made a big difference.

Thanks yet again for the responses...

 

[gooniac33]

If you have not tuned up your car then there is the issue. A car with 70k miles will need plugs at least. Thats just my 2 cents.

 

[kemerick]

I forgot about this post and moved on... it actually ended up being the throttle body in case anyone reads up on this post and has the same symptoms.