Acceleration hesitation

speedracer · Post by **speedracer** » Thu May 25, 2006 9:05 pm

Hey recently I've noticed that I'm getting a moderate amount of hesitation around the mid range portion of my rpm range (around 4000). I checked all of my plugs and wires and they seem to be okay, except for some oil on plug #4, but the oil wasn't touching the electrode or the insulator.

I don't think I have an intake leak. Could this be an internal problem or is my pcm going ape shit?

People who have had this problem, what was it and what did you do for it?

I realize that this could be a # of problems, but I'd like to hear other's experiences. Thanks, Paul.

kc2005ptgt · Post by **kc2005ptgt** » Thu May 25, 2006 10:28 pm

atx or mtx? edit: just saw your sig, mtx

does it only hesitate at the 4k mark? our cars suck in the mid range, specially with a lt header.

is it a magnum engine, or just the intake and no head?

do you see any oil leakage anywhere under the hood, down low, in the back?

also, try changing the plugs with good old champion (stock) plugs - that always helps!

sorry I couldn't be more help.

BlackRoseRacing · Post by **BlackRoseRacing** » Fri May 26, 2006 6:10 am

Whats the AEM cam gear set as? straight up 0deg?
Sounds to me like you have a descent amount of bolt ons for an NGC car. Its always possible that the PCM is going nuts trying to figure out your new airflow...
Disconnect the batttery and remove the fuel pump relay, let it sit over night. Then the following morning reconnect the battery pop the relay in and take it for a spin. See if there is any change then. On NGC cars it is always a good idea to reset the PCM after every bolt on that modifies the airflow or fuel requirements of the motor...

OB · Post by OB » Fri May 26, 2006 10:29 am

does the relay have to be removed to reset the PCM or does just disconnecting the batt for a while do the trick on its own? where is the relay located, in the fuse box under the hood?

btw, ive also experienced quite a bit of hesitation, and ive found it to be caused by a particular action: when youre driving normally and u depress the clutch pedal, let of the throttle, then without switching gears or anything, try to release the clutch and get back on the throttle, the car badly hesitates, sometimes for several seconds. it works almost every time i test it. driving in a parking lot in 1st and then using the clutch to regulate speed (normal parking lot driving basically) is the most common place i experience it. or coming up to a red light that turns right before u stop, then trying to stay in gear and go again, also causes huge hesitation every time. ive grown used to it, but id do anything to get rid of it. feels like 'drive by wire' even tho its not. Im pretty sure its a fuel cut from the PCM ancticipating a stop. it prob cuts the injectors in order to improve mileage, thats my theory at least. sometimes its so violent it feels like the brakes have been hit and it jerks the car forward instead of accellerating. anyways, rant rant.

my prob has nothing to do with the midrange specifically, so i dont know if its a common problem or if theyre unrelated.

speedracer · Post by **speedracer** » Fri May 26, 2006 10:39 am

Yeah, I've tired resetting the pcm and inspecting all of my ignition stuff, and it still hesitates. It feels like the car is pulling mad timing around 4k. My cam gear is set at 2 degrees advance by the way and it has been for over a year now. This hesitation thing has only come on now for a little over a week now.

I've only had my spark plugs for about 6k miles now, but I'm going to try to change them today anyway and see what happens. I'm also going to do a leak down test and see if it's a vacuum leak. I wish I had a compression gauge, then I could do a cylinder compression test. I would think that with only 39k on my car the pistons should be fine though. Thanks everyone, Paul.