TOPIC: 2004 Corolla

Just got my personal license. Plan to groove a 2004 Toyota Corolla, which I bought specifically to play with the mileage. Have Pulstar plugs to install when weather gets warmer...do NOT have a garage. K&N filter won't go in till I take a nice trip to see what my mileage is BEFORE. The trip will be this weekend. Am I using too many words??? Am new to this FORUM stuff.

welcome aboard vince sounds like your ready for the first steps. dan gadgetman mo.

The trip was all interstate through New England and I got 40 MPG with all stock. Later did 300 miles around town and got 30 MPG. Think I'll groove the lawnmower first for practice, but will install the Pulstar spark plugs and K&N filter to help clear my workbench. 4/13/12

Hi Vince,

welcome aboard.

Did you see the post regarding the change in how the groove angle is set?


Worth doing some browsing through the forum here to get a good mental picture of the whats and how to's.

Karl Fortner
Tacoma, Wa.

Welcome Vince,

I recommend that you Groove the Corolla BEFORE you change the plugs and air filter. The air filter may not be good for the Groove. If you do the Groove first, you will see it's total effect. Then you will see how the other changes will enhance or detract from the Groove.

OK...finally tried to groove the 2004 Corolla. Found the salt air, salty rain and salt on winter roads here in S. New England has corroded/locked in place the accelerator cable and then we (son and I) snapped off the corroded head of the bolt holding accelerometer spring assy trying to get past the locked in place acc cable. We dropped the hood and gave up on the car.

Son wished to groove his 2007 Corolla, with a much simpler throttle body....NO accelerometer cable, it is all electric. Son Mike did the groove. PCV valve output has been run into the air cleaner, and the original PCV valve connection/hose has been sealed off. Upon start up. idle RPM is at 2500 and slowly lowers as the motor warms up. When driving, in drive, and stopped at a light, rpm goes to 1100, which seems normal for his and my car.

The high idle rpm at start up has me concerned. We are open to suggestions as cause/remedy of the High cold RPM issue.

Hi Vince,

First question I have is which method did Mike use to determine the throttle plate angle to place the groove.

Karl Fortner
Tacoma, Washington

Sounds like the Groove is a bit too close to the throttle blade at normal idle position. Happened to me on an 06 Chevy Avalanche w/computer controlled throttle.

I second Karl- how was it decided where to place the Groove? Can use a scantool to find idle position of throttle blade at engine warmed-up idle, then add say 2-3 degrees of throttle blade angle to idle position for start point.

Ron has also pointed out to look for the dark stain in throttle bore--the edge of that stain is the normal hot idle position. Think he said add 1-2 millimeters to that as start point.

Anyhow how did you guys figure where to place the Groove

Pics of your work would help a lot!

TracyG Gadgetman Reno

Mike and I got under the hood of the 2007 Corolla yesterday. I suspected the high idle problem was a vacuum leak, so we pulled the TB and inspected the surfaces where the o-ring on the motor meets the TB surface. It appeared there was good mating. Next we looked at the vacuum line that was originally on the PCV valve, and found the cap closing off the vacuum line was not as tight as it might be. Applied some blue RTV to the inside of the cap, pushed it on the vacuum line, and let it sit for the night. This morning we started the car and had a rock steady idle of 2000 RPM while cold. Looks like the high idle RPM was caused by a vacuum leak.

Mike's groove is a bit further away from the throttle plate than I would have placed it, but it is his car and his groove. We wait to see if the onboard computer will allow us a milage gain.

As to the 2004 Corolla, I am still unable to remove the accelerator cable from the TB. Just can't get passed step one.

Hey Vince,

Nice catch, never hurts to retrace and double check... over time what I previously thought was pretty good, I now look and and tell myself... I could have done better.

Keep'em coming

Karl Fortner
Tacoma, Washington

Vince wrote: Mi
As to the 2004 Corolla, I am still unable to remove the accelerator cable from the TB. Just can't get passed step one.

Vince, I am glad to see you posting!

On any mods where you're having problems such as removing the cable (or whatever it may be) it helps for you to provide a picture of the offending instrument. With that, I can tell you how to remove it, for certain.

As always, I am available by phone for a consult, but please continue to post here before you call! Otherwise, I'll have to get back to you...

Mike has a job in N. Providence with both highway and stop and go driving to and from home. He was averaging 29 MPG before his groove in the 2007 Corolla. For the last two fill-ups he has measured 34.5 and 35 MPG....a nice 20% increase!

Hope all the Gadgetmen and their families had a most enjoyable Thanksgiving.