describe the hesitation better, clean up after half throttle like a switch? constant? rpm limited? im near rochester ny
jason

 

When the idle is at normal 750rpm and that the engine is at normal temperature range, when im at a dead stop,if i punch the gas quickly the car buck 3-4 times than pull hard.

But right now there is other issue like i ve stated.
It sometimes idle a 1000 or 1300 or even 1500rpm.
It seems to be running to lean than to pcm recalibrate and running to rich.
Im also getting knock everywhere in the rpm range and the pcm is pulling 3.5 to 5 degree of timing advance.

 

I'd take a look at your log as well.

Sweetred95ta@hotmail.com

Have you verified whether the knock retard is true or false? I'd start with that. I can't help you though with a shop near NY.

 

I don't see any real mods to the motor, why are you running 32lb injectors? Hesitation could possibly be caused by too much injector.

 

You realize that most trouble shooting is like that? You make your best guess and go after that first, working down the list from most to least likely. Or more accurately from the likely, to the unlikely, to the improbable, and finnally to the bizzare!

Rich

 

Lt4 engine came with 28lbs injectors so i dont think that the 32lbs are a problem.

 

Log have been sent.

Thanks

 

I totally understand that and maybe i was not precise enough.

I wanna a shop that know f-body,not just a normal mechanic garage that do oil change and rotate tire for 90% of there business.

 

Alrighty. Your car idles funny because the TPS is showing .8% (.71V) when you have your foot off of the throttle. You may need to do the slot mod to the TPS to get the voltage down. I would also make sure the tb gasket isn't ripped around the IAC passage. The car hesitates off idle because you're getting knock retard at WOT. Off idle, with the knock retard, the car is seeing 16* of timing advance. Finally, you need work on your MAF Calibration tables. The long-term fuel trims are showing the car wanting to run lean.

You're not going to be able to go the NY, find a reputable SHOP, and get these issues resolved. Most of it is tuning. Like I stated above, you need to verify whether or not that knock retard is true or false and go from there.

 

Drop the TPS voltage to around .6(.55 for 93's) for much crisper off-idle response, then reset the TPS so it shows 0%.

Also, quickly find out if the knock is real or false with some race gas. If there is less timing pulled with race gas it is either real, or mix of real and false. You can start by scaling down the attack tables 15-20% across the board to see if it helps. If not its most likely false, but with so much knock retard even at idle, no wonder its running like crap.

 

There is a shop in WNY called PM Performance
They are located at 108 Sawyer Ave Tonawanda, NY 14150
They both do ALOT of LT stuff and are f-body specific.
The Guys names are Paul and Mark
They are also on the board, Marks name is Bad AZz Z28
and Pauls name is nytrus1. they are not on this board too much. but...
hop on www.newyorkfbody.com and pm them. they can help you out.
They also do computer tuning too.
There is also New Era Performance in Rochester, NY.
Website: http://www.neweraperformanceparts.com/

Good luck I hope you can figure it out.

 

Well thanks for the heads up.The weird thing about the tps is that i made another log a couple of minutes after the 3 that i ve sent you and the tps was at 0% and idle at around 750rpm...

MAF calibration,long term fuel trim,i dont even know what this is

How can i clearly find if there is true or false knock except with race gas?

 

Thanks for the hint.I ve sent a form the become a member on the new york board and will try to contact one of them.

 

Yeah, my idle does the same thing sometimes. Just try dropping the voltage down and seeing if it helps. Have you verified whether or not the tb is sticking?

Well, the MAF calibration tables directly effect your short and long term fuel trims. They're tuning terms that show you if the pcm is having to add or subtract fuel to achieve a stoichiometric a/f. Simply, it's a tuning issue.

Another way to check and see if the knock is true or false is to make timing adjustments and see if there is any change in the knock retard values. Use some Xylene to increase your gas's octane rating. Do a search about it. I just saw a post on it a yesterday or so.

 

If you have any problems getting on the board, let me know. I can contact them for you.