baggs32

I have an '06 GT with manual tranny and the only lag I get is when I want to blip the throttle for downshifts. Every time I try to do that I have to pump the pedal twice to get it to respond faster. The first pump will eventually respond after a second or two but I found that if I pump it once real quick then again I can get a faster response.

Anyone else notice this and will this little trick help out?

metroplex

That is not really throttle lag. You have to hold it down more because of the dead-play in the throttle.

I really wish a vendor would make a revised throttle sensor that eliminates the dead-play from the get-go.

theedge67

They do. It's called an aftermarket tune. You should really look into these novel little creatures. I think you would be singing a different tune about your throttle dead play if you drove a GT with a good 93 octane tune in it.

touring

The problem with the lag is because you dont have a tune !!!! dont think a tune will not fix it cause it will

atomicvibe

Here's a little update to my issue:

Car's been running great for about a week now.
The RPMs have evened out; no more erratic revs or extremely long RPM lags.
And the car's been very responsive, overall.
She's been quick off the line, and feeling like new again.

Except for tonight.

I was sitting in about an hour's worth of stop and go traffic, and once it cleared, I stomped on the gas, and the car responded in much the same way it had before I had the TB cleaned and the loose connection between TB and CAI tightened: VERY sluggish.
I probably couldn't have chirped tires off the line if I tried.

Now, the CAI filter definitely needs to be cleaned, but I can't see this as being the main issue here, since the car had been running so well for the past week.
And I know that a custom tune will boost performance.

But I don't understand how an hour's worth of stop & go traffic can affect the car so badly.
It's like the car pulled a Jeckyll & Hyde on me.

theedge67

Hot air my friend. Hot air. All the sitting in traffic got the intake air temperature waaaay up and that will cause pretty significant loss of power.

SStang

Mine does the same thing. There's no physical dead play in my throttle assembly. If I barely push it at idle, the rpms go up. I don't think there's "tune lag" because if I stab it rolling down the road, either the car jumps forward or the tires spin like crazy.

But a blip seems to do nothing on downshifts. I haven't tried a double pump, but I have to really give it a big pump to make something happen, and then sometimes it revs up a lot more than I intended. Only thing I can think of is maybe the computer is doing something to over-ride my little blip since I'm on the brakes? I'll have to try it just coasting down and not braking.

baggs32

That's exactly my experience. Only you explained it a little better.

Heel and toe shifting is pretty much impossible because of this so I might try this trick to see if it does anything at all.

I actually had a weird thing happen the other day. I was driving along a busy road and wanted to pass a minivan. I stomp on the gas, begin to pull over to the left lane, car goes like hell, minivan pulls over in front of me! So I let off the gas, car slows down, inch back over into the lane I started in and was still 3/4 of the way in, stomp on the gas again, and NOTHING! It felt like the fuel shut off to the engine because it slowed down or something. Now the two stomps on the gas were within 2-3 seconds of each other and the RPMs were still pretty high from the first stomp. Did the computer shut the fuel off to save the engine from damage maybe? It was very similar to the sensation you get when you hit the rev limiter. After that happened I shifted to 3rd (I was in 2nd gear when this all happened), stomped on the gas again, and took off like a bat out of hell.

Any thoughts?

theedge67

Maybe you did hit the limiter? I've hit it before once or twice when I was not planning on it, and it was unexpected. It comes up quick in 2nd. Other than that, I have no idea.

baggs32

Yeah, either that or the TCS system predicted that I was going to spin the tires hard. I don't consider it a problem at all. I'm just curious as to what system stepped in and shut off the gas. Obviously the computer saw a problem with what I was doing or even potential disaster. It's hard to imagine it was the rev limiter though because the RPMs were decreasing after I let off the gas without hitting it on the first gas pedal stomp. When I hit it again I got nothing meaning it never had a chance to rev back up to hit the limiter. Maybe I was high enough in the RPMs to make the computer think I was going to hit it fast and took appropriate action?

Sorry to be somewhat OT but since this involved the throttle I thought I'd ask here rather than starting a new thread on something so trivial.

theedge67

Well, it does not sound likely it was the limiter given you were dropping rpm's before you hit it again. Momentary loss in fuel pressure? Don't know why that would happen though...

baggs32

I wouldn't call it a momentary loss of fuel pressure. Fuel was plain cut off by the computer. Will that show up as a code that the dealer techs can read off for me the next time I'm there for routine service?

metroplex

It's a defective throttle body / throttle sensor.

My 07 GT has the throttle dead-play. I can kick the throttle all day long and not have the RPM's rise at all unless I go a bit further with the throttle opening. The dead play is a physical design flaw of the throttle sensor and no amount of tuning will solve it.

baggs32

I think that's actually something different. What theedge67 and I are describing only happens when trying to blip the throttle before a downshift to match the tranny/wheel revolutions. Most likely braking is happening or has just happened too. I get an immediate response from the throttle any other time with no discernable dead play.

theedge67

Have you tried a tune to see how much of the dead play and throttle lag disappear? I think you might be suprised.

SStang

I don't think that's the issue with the blips on downshifts. Something is making it not respond the way it does at any other time.

Fix it! I know you've seen the thread in the other forum. I would try the method of moving the cover with the screws loosened before bending the brushes. Maybe pick up an assembly from the dealer to have as a backup if you're afraid of breaking something.

metroplex

Wasn't there a TSB on this related to cavitation/foaming at the fuel pump, causing a momentary loss in fuel supply?

theedge67

This is not caused by the condition described by the TSB. That only happens after a long cruise while at steady throttle. Air bubbles form on the pump housing, and are sucked up when the throttle is hit hard.

He already was on the gas hard for a few seconds before the hesitation hit. It would have already cleared out any air bubbles by then.

metroplex

He has a 2006, it might be the same thing...

m05fastbackGT

It seems that what you may be describing is throttle hang. However since upgrading to my Bamachip's 93 torque and race programs. There have been no further deceleration/response issues, related to throttle hang.