2005 GTP Hesitation/Sluggish

[Corey Prashker]

2005 Grand prix gtp stock it hesitates to accelerate, sometimes car feels very slow. Sometimes it acts very normal and is a rocket. I changed plugs wires... just tired of throwing money at the car. I even had the PCM updated at the dealership. I did notice that problem seems to go away when I restart the car sometimes.

Another way to explain issue is say I'm at a light. I press throttle 1/4 of the way, sometimes it accelerates very slow. When the car acts normal it squeals the tires a bit.

I do see that two members fixed the issue somewhat with an aftermarket PCM tune. Any advice is greatly appreciated as this is making me go crazy.

[Fivefingerdeathpunch]

What brand plugs?

To help, I would remove the throttle body and clean it, I bet its all black and nasty. Also remove the MAF sensor and clean it with MAF cleaner.

Just doing those 2 things can help alot.

[sLpGPGT]

does it happen every once in a while then u restart the car and problem solved?
EDIT: cause mine does the same thing

[Corey Prashker]

plugs are new tr55s but it did same thing with old ones. I also cleaned the throttle body and maf last month.

sLpGPGT yes if happens once in a while and seems to go away when car is restarted. Although today went to store and got back in car and it bogged exiting the parking lot.

Almost seems to do it more when I turn.

[sLpGPGT]

mine just does it in the lower gears, in 3rd is seems to go away but still sluggish when shifting in higher gears but in higher gears it dont chug, i got no idea wat my problem is either but id thought id relate a problem with someone else haha

[Corey Prashker]

Could it be the transmission as sometimes the car revs and clunks into gear at a light. Maybe the transmission is sticking or causing a hangup? Could it be the transmission as sometimes the car revs and clunks into gear at a light. Maybe the transmission is sticking or causing a hangup?

[acidcrashdburnd]

My 2005 GT does that. It did it before and after the top swap. I think it has to do with heat and humidity. Causes the timing to change.

Sent from my Galaxy Nexus using Tapatalk 2

[SlprGS]

my girlfriend's 2005 is doing that also. We just picked it up so I'm gonna do a routine tuneup on it sometime this week..

[GMCustomerService]

Corey Prashker,

This issue may be caused by a non-holding torque converter stator or damaged stator support shaft within the automatic transmission. This is just a suggestion, not a diagnosis. You may want to consider having the vehicle inspected by a certified technician.

Please keep us posted.

Louis
GM Customer Service

[t24moore]

A bad oxygen sensor can cause that. Do you have a CEL light? Do you know of anyone with a OBD scanner? If youre going to spend any more money buy yourself a scan tool.

[blueguy]

buy yourself a scan tool.

This.

[Corey Prashker]

I have a very good scan tool. How would I go about checking if the o2 sensors are bad? They seem to be putting out a voltage and it switches... is there a certain value?

[t24moore]

You usually can just look at the logs and see if the values constantly switches. It should never remain high or low. Only time it should lock into one voltage is when you go WOT. One question tho, does the car do this when you first start it up or after its warm?

[Corey Prashker]

I took the car to the stealership and they played with it for a few hours and I left it overnight. They said it didn't act up but it was probably my Hot air intake (cone filter on the end of maf) Is this possible? What do I need to do to be able to run this type of filter? Would a PCM by overkill be programmed to allow for new maf settings?

[Tuner-Extraordinaire]

Tune won't do a thing for you there.

Put your stock stuff back on.

[Rico]

I took the car to the stealership and they played with it for a few hours and I left it overnight. They said it didn't act up but it was probably my Hot air intake (cone filter on the end of maf) Is this possible? What do I need to do to be able to run this type of filter? Would a PCM by overkill be programmed to allow for new maf settings?

Put some distance between the filter and the MAF.

[Corey Prashker]

Ok guys just as an update, car seems to run better for a while after you give it a few WOT runs. At 3200 rpms at medium throttle car suddenly develops a surge of power, feels like a vtech boost. My supercharger bypass valve seems to be working... Could this ALL be a THROTTLE body issue as the TPS, servo motor are all in this unit. Maybe its getting stuck? I did take it off for a thorough clean (wasn't very dirty).

[lawadm1]

I have a 2005 GTP, and it runs absolutely perfect when the engine is cold. But after the engine warms up, sits for 20-30 minutes, and I restart the car and take of. The car acts like it's not getting any gas, sputters, and will hit 4000rpm just to get going. I always use the Shell 93 V-power gas in it, so I don't think I have bad gas. And then after the engine cools off for a few hours, boom, it's a rocket again.

Any ideas? I love this car, but this is really annoying.

Jeff

[Rico]

Ok guys just as an update, car seems to run better for a while after you give it a few WOT runs. At 3200 rpms at medium throttle car suddenly develops a surge of power, feels like a vtech boost. My supercharger bypass valve seems to be working... Could this ALL be a THROTTLE body issue as the TPS, servo motor are all in this unit. Maybe its getting stuck? I did take it off for a thorough clean (wasn't very dirty).

Did you put the stock intake stuff back on like Nixon suggested?

[Rico]

I have a 2005 GTP, and it runs absolutely perfect when the engine is cold. But after the engine warms up, sits for 20-30 minutes, and I restart the car and take of. The car acts like it's not getting any gas, sputters, and will hit 4000rpm just to get going. I always use the Shell 93 V-power gas in it, so I don't think I have bad gas. And then after the engine cools off for a few hours, boom, it's a rocket again.

Any ideas? I love this car, but this is really annoying.

Jeff

Check for codes yet?

Sound like your PCM is pulling timing when it warms up.

Is the car stock?