yello1stang

Pull up a chair and grab a soda, this may take a while. I am the owner of a 2001 Mustang Gt. Mods include Steeda G-Trac suspension, caster camber plates, Tokico shocks, Aluminum rear control arms, underdrive pullies, throttle body spacer, C&L Cold air plenum, 80 mm MAF and filter. Motor is basically stock. My problem is a surging sensation that takes places while driving. Hard acceleration, mild acceleration, highway cruising, if feels as if your sitting in a rocking chair. Have had injectors cleaned, installed new plugs, compression checked, diagnostics run!
No codes, no fuel/air ratio problems, no apparent miss. Ford dealer says they are no prepared to deal with modded stangs!!!! WAS wondering if anyone else might be experiencing the same problems.

ibeeskeef

sounds like plugs and plug wires. I know you changed the plugs, did you change the wires as well?

Aixtreme89

I was having that kinda problem when I installed my accufab upper intake plenum and throttle body, and Mac straight shot cold air intake. I unistalled and reinstalled my upper plenum so many times. That it eventaully went away. But check your vaccum lines that corrospond to your intake plenum and cold air intake.

04BlueGT

If the 'surging sensation' happens when you push hard on the right pedal, that is normal!

Seriously though, I've never heard of this. My only ideas are:

Check the voltage on your TPS. I don't have the info in front of me for the TPS, but plenty of folks here can help you with that.

The IAC could be fouled, expecially if you run 93 octane in the car. Take if off and clean with carb cleaner if necessary. Granted, this should NOT be the problem, but it can't hurt to look.

JD1969

Not to pick on you, but 93 octane WILL NOT do this, I am however interested in why you say this. This might sound funny but try rotating the MAF, somtimes when a CAI is instaled the airflow hits the MAF funny and causes it to misread, I've never seen cause a surge at all RPM's, mostly during idle, but it's worht a shot.

GSXRIntensity

I would suggest like above checking the TPS, or IAC. If you have not had your car tuned, I'd run 87 in it. I have to run 93 or better in my car now, cuz it's been tuned for it, but beforehand I ran 87. I tried 93 for 6mths when it was stock & brand new. I eventually developed hard starts & a rougher idle. I went to 87 one day I was on 'E' & immediately my car started & idled smoother. Now however...nothing less than 93.

04BlueGT

The car is set up to run 87. Running 93 can cause deposits to build up in the intake and IAC (or so says my mech). Like I said, I seriously doubt that this is the issue here. The car is not nearly old enough.

JD1969

I want to make it clear that I am not trying to make you look bad or start a fight or anything. I have a question. How can it cause build ups and deposits when there is no fuel flowing through the intake? Remember that fuel is introduced with the injectiors just before the intake valve (at least on a newer engines), same goes for the IAC, it does not see any fuel. It seems there is a lot misunderstanding when it comes to octane and what it really does. Simply, it is a measurement of how resistant a fuel is to preignition, it does not have any funny addatives that cause build up or anything, it actually is more refined than lower octane levels. True that 93 will not give any noticable power in most cases, it will however allow the computor to run as much timing as possible, which can result in a very slight power increase.

Sidewayz6.0

There are no plug wires on an '01 GT. It's the same set up as your '03. Coil Packs that attach right to the top of the spark plugs.

Fallstar01

The throttlebody spacer is the most suspicious of your mods. Get rid of it because many of those things try to mess up the air flow and cause turbulence which is BAD not good. Especially those stupid ones with the screw type inside. Other than that, make sure you seriously tighten up everything so that there is no unmetered air coming in. It's also important to check for exhaust leaks and vaccuum line leaks. Also, stick that stupid screen back in before your MAF if you took it out.
If this doesn't work, check your air filter for holes. Finally make sure to check your fuel filter. Sometime sensors can just go, your O2 or MAF sensor could be faulty but 99.9% of the time they would throw a code.