03 Matrix P&G Woes

[Daox]

I have been working on refining my P&G technique with my Matrix, but I'm having a problem. Once I get up to around 60-65 mph (90% of my daily drive) and push in the clutch, the engine does not idle down right away. The rpms stay constant for a few seconds, then drop very slowly. This obviously hurts my glide a LOT (100mpg vs 300-350 when it drops to idle). Sometimes the rpms will drop down to normal idle speeds, and other times it won't. It seems as speed increases, so does this tendancy to not idle down right away. I guess I'm curious if any Celica/Corolla/Matrix owners have this same problem? Its a base model, so it has the 1ZZ-FE engine. Another thing is that I am running an E-manage and Zeitronix wideband O2 system on the engine and I'm wondering if this is effecting it. I have found I can usually drop the rpms back down quickly by blipping the throttle quick, but this again hurts economy and adds one more step to the extra work of P&Ging. Anyone have any ideas on this?

[trebuchet03]

My father's Element did this very same thing.... For him, it was a sticking IAC valve

[Daox]

I'll check that. I just find it odd that it never sticks at low speeds.

[1993CivicVX]

what happens if you rev the engine in neutral up to like 4500 rpm and then take your foot off the gas? How quickly does it drop down to idle then?

my car was doing something similar. At low speeds the idle would actually increase. Cleaned the IACV and the throttle body and now it behaves nearly perfectly. Still a high idle but no more roaming or odd behavior. My mechanic says my idle would drop down to 550 (it's normally is at 1100) if I were to rev the engine more instead of driving at 1500RPM because the engine is never getting warm enough to idle at the lower RPM.

[laseradam]

I have a new 2007 corolla with about 3,000 miles on it. When I shift into neutral at 50 or 60 MPH the RPMs stay around 1,200RPM. then slowly drop down.

Sometimes though it seems that it will drop straight to in the 600 RPM range. I havent got it figured out yet either.

This is all with the engine well warmed up.

[SVOboy]

Usually, I have noticed, cars will idle lower when stopped then when moving, dunno why, but I think it's in the ecu, *shrug*

[Daox]

Originally Posted by 1993CivicVX

what happens if you rev the engine in neutral up to like 4500 rpm and then take your foot off the gas? How quickly does it drop down to idle then?

my car was doing something similar. At low speeds the idle would actually increase. Cleaned the IACV and the throttle body and now it behaves nearly perfectly. Still a high idle but no more roaming or odd behavior. My mechanic says my idle would drop down to 550 (it's normally is at 1100) if I were to rev the engine more instead of driving at 1500RPM because the engine is never getting warm enough to idle at the lower RPM.

If I rev it in neutral it idles right down like it should, never gives any problems like that. The RPMs never drops down lower than they should. Its only at higher traveling speeds that it does it.

Engine temp is not a problem. Traveling at highway speeds keeps my water temp right at about 180-185?F.

That is what I'm trying to figure out SVOboy. I think your probably right, but I want to know for sure. If it is the ECU... well, then I'm stuck with it.

[slimreynolds]

Hey doax, I have a 04 matrix. Try letting off the gas a split second quicker before you hit the clutch. I do p&g too but at lower speeds (55) and I don't have this problem. But at higher speeds it will happen quite often. By the way, you should be getting way better FE numbers with your matrix. I usually get 45 mpg and my car has 252,000 miles on it. The matrix has a lot of potential.

[Daox]

I have noticed at 55 mph it very rarely does this. Its really only once I get up to about 65 that it does it consistantly.

The mileage issue is another thing. I carpool with the wife in to work and back. She is a horticulture technician, so she drives the car around the city all day for her job. I just drive to work, she takes off, then picks me up when I'm done and I drive home. She won't P&G. I usually average 40-45 on the way in to work and back according to the scangague which I think is a bit high (still dialing it in). That is only P&Ging halfway due to this problem.

Thanks for the input fellas.

[Sille]

Hey DAOX,

My AWD VIBE (Same Engine) does not seem to have this issue. However, I do have an auto tranny.

The curious part with mine is at a stop. Idle in drive is around 800 rpm and Idle in Neural at stop is about 1100-1000 rpm