MPG drop, low idle

Hello, all.

I've recently had about a 1 MPG drop. I'm also noticing a low idle. The low idle is rough and just above 500 RPM. It is most noticeable within a few minutes of starting the truck.

It has been about 40k miles since I changed the plugs, but I'm thinking of doing it again just off a knee-jerk.

Do y'all have any other ideas?

Thanks,

Matt

 

Inspect/clean your MAF maybe. I'd also maybe run some fuel injector cleaner in it, change the air filter, and depending on when it was done last maybe your fuel filter as well

 

Clean out your Throttle Body for the Idle and honestly a 1pmg drop is pretty minimal. Maybe you have been using the A/C more or driving differently. Just my $.02

 

Air filter has 1k miles on it.

I cleaned the MAF, but I don't recall when and it's not in my notes, so I'll do that.

I run fuel injector cleaner through it at every oil change.

Fuel filter as 34k miles on it. How long do they last?

 

Spark plug shopping - NGK BKR5EKPB-11 seems to be the platinum plug for this truck. Amazon has it for almost $10 a plug. Does that seem right?

If so, I don't think that's what I put in it before. I think I'd remember that big a bite in the ass for spark plugs. Maybe I put copper plugs in and they are now shot.

 

sub'd for answers. I am having the same problem. I changed my air filter and thought I had it fixed yesterday, the problem is back today.

I cleaned my throttle body about a month ago as well as my MAF. I am due for spark plugs, but I think it is more of fuel delivery issue rather than an ignition issue... Just a hunch though.

 

40K on good plugs should be nearly nothing. $10 a plug is ridiculous for a Tacoma,

http://www.rockauto.com/en/catalog/toyota,2004,tacoma,3.4l+v6,1429084,ignition,spark+plug,7212

You're throwing your money away

 

Much better price. The same plugs I was looking at on Amazon are $6.52 on Rock Auto. I still don't think I put those in. They are listed as "double platinum". I suspect I put in "platinum", which are a couple of bucks a piece, which is not so high that I'd have been shocked into remembering.

So, probably not a plug problem.

As to your previous comment about 1MPG not being much, I agree. However, it has been consistently lower for about the last 5 fillups. That's more than a 5% drop. I don't *think* the AC would account for a 5% drop in gas mileage.

 

Is it throwing any codes at all? My A/F sensor was on it's way out and I noticed a drop in mpg's, can't remember if it had a low idle.

 

they are "twin-electrode" and I paid about $5-6 each from Autozone/Advanced.

Amazon will have multiple listings for the same items, it all depends on who has them listed and if Prime is offered or not.


also, yes, the A/C will suck the life out of the 2.7 & 3.4 and reduce mpg if used regularly. due to a less flat terrain I rarely ever use the A/C. only when it's above 80-85 and humidity is high. otherwise roll the window down and enjoy some air

 

Yeah, I'm familiar with both the plugs and Amazon. My mistake was not looking at the NGK product line well enough and pricing "double platinum" instead of a more moderately priced plug.

I live just north of Atlanta. Every day, all summer - humidity and temperature start with the same number and it's an 8 or a 9.

 

No check engine light. I haven't put a code reader on it.

 

I have heard that not all air filters are created equal... do I have proof of this, no, having said that, are these factory air filters, K & N or off the shelf parts store units? When I did some research on air filters if you go to the K & N site, of course K & N filters are superior, Wix makes the same claim so...

 

You might not get any codes. I have a similar issue on my 04 DC. Idles around 500-600, and I'm getting like 12mpg in the city (stock except 265/75 A/T's). I've cleaned the MAF, air filter (K&N), throttle body, injector cleaner, etc... No codes, ever. My next option is to actually replace the MAF and/or the upstream O2 censor.