Part Throttle issues

[dipapa]

Well i got part throttle issues.

Anyone had poor part throttle issue and know possible causes?

Its a lazy part throttle..noticeable car is dragging at part throttle at all rpm mostly in 3rd & 4th giving foot pedal 1-5inches of throw.

Laying into throttle slowly car aint pulling real strong... on part throttle acceleration, rpms going up, motor sounds loud but just a sluggish lagging feel.
Like something stuck in exhaust or cats are plugged. I dont have cats and exhaust flows fine.

so the part throttle is not a crisp, responsive feel like it should be. WOT dont feel too bad.


Couple Other symptoms but just an observation. I just think its all related.

I get iginition startup "hiccup". Motor cranks, then blanks out for a fraction of second and then starts up. kinda of a weak startup.. as soon as motor turns over it goes low rpms 300-400 for a few seconds then idle stabilizes to 700 rpm.

When rolling into a stop the rpms drop to 300-400 rpm for 5 seconds like motos about to stall, but doesnt then regains rpms to 700.


I have an SCT tune.
American Racing headers.
no cats
stock mufflers.
X Metal

Air/Fuel gauge bounces around from uper 13's to upper 15's.
Throttle cable is tight.
no codes.
Idle for most part is fine.
nothing unusual visually
All mechanicals are completely intact.


Biggest problem complant is the part throttle lagging feel. It *****. I got smoked by a few much less poweful cars.. that really hurt

Wondering if any one had part throttle issues or has a hunch at what it could be.

Can turning off long term fuel trims cause a poor part throttle?

Can not enough part throttle fuel enrichment cause this?

I'll be towing car to A&C Performance next week. Hopefully Todd can find something.

Latent Electrical Anomalies really ****.

I ordered a new PCM. I hope its that simple.

 

[swexlin]

My first thougt is the battery, especially for your startup issues. See my "odd cold start" thread from a couple months back. A new Sears Diehard cured me. Maybe your other symptoms are also related?

 

[ROCKET62]

Have you noticed more low speed "bucking" with your Xmetal throttle body? My first thought was throttle position sensor. It is slightly adjustable and you can check the output with an ohm meter. I forget the ranges and a search of throttle position sensor might lead to the post on it.

 

[dipapa]

My first thougt is the battery, especially for your startup issues. See my "odd cold start" thread from a couple months back. A new Sears Diehard cured me. Maybe your other symptoms are also related?

Yeah I thought the same thing and installed a new interstate battery 3 months ago when I started noticing the ignition startup "hiccup".

Seemed a bit better fir a short while but ultimately didnt help.

It's unusual because motors is just about to fire, then it cuts out, then it fires up with rpm's struggling 300-400 for a few seconds and then stabilizes to a 700 rpm idle.

The startup ain't bugging me but I think it may be related to the part throttle being affected???

 

[dipapa]

Have you noticed more low speed "bucking" with your Xmetal throttle body? My first thought was throttle position sensor. It is slightly adjustable and you can check the output with an ohm meter. I forget the ranges and a search of throttle position sensor might lead to the post on it.

A new TPS was installed at time of built motor about 8 months ago and it was set properly.

I'm not sure if it's the TB but my car does buck a bit. I like that seems normal. I've had other cars that did that a bit too.