Need help with GT engine surging....

[blucobra03]

I have a 96 GT with some mild mods as below:
K&N Flitercharger
Offroad H-pipe with 2 chamber flowmasters
Superchip
Transco shifkit
Royal Purple Synthetic oil

The problem is that whenever cruising the engine starts to surge about 50-100 rpm every few seconds then stops for about a minute or so and does it some more. You can hear the surging in the engine more than you can see the tach move. It only does this with the A/C on too. It just started doing this about a couple weeks ago. The mods have been on there for a couple years now. I thought maybe the fuel filter might need changing, so I did that and no difference. The car has 86,000 miles but is in great shape and very well taken car of. Does anyone have any ideas on what might be causing this surging ? Any help is definitely appreciated as it's about to drive me crazy.

 

[Blackgeetee]

Sounds like it could be a vacuum leak or possibly some sort of bad sensor. I would first try resetting the computer by disconnecting the negative batery terminal and see if that helps. :beer:

 

[Ryan]

clogged EGR maybe? Any codes? CEL?

 

[Blown306]

Take a look at the IAC...with 86k on the clock, it's probably pretty gunked up. It controls more than just idle airflow, it's used when the a/c is on, coasting, and dashpot.

 

[RAP66]

I had the same problem on my 91GT... I replaced the EGR, TPS and the one that helped the most was removing the throttle body and cleanin all the smudge on the butterfly... That day I bought stock in Berryman Chemtool:shrug:

But afterwarsd that surging was gone.

 

[blucobra03]

I appreciate all the help guys. I have to admit that I don't know what the IAC is so I can't check it. I did pull the K&N Filtercharger off and cleaned it up. I sprayed some Gumout into the throttle body while running to clean some of the tarnish out of there. I hate to be a dumbass, but where is the MAF and/or sensor and if I wanted to change out the throttle body, which size would you think would be the best for my mods ? Is it difficult to change it out, any special things I should know ? Is the MAF something I can increase in size as well to help the engine run better ? Also, is there a way for me to check for codes without going to the dealer ? Sorry for all the questions and I do appreciate all the help out there. Thanks !!

 

[Ryan]

MAF (Mass Air Flow Sensor) is attached to the airbox (the lil round thing with the black box on top, with a plug plugged into it). The IAC (Idle Air Control Valve), IIRC on the 5.0 is on the side or really close to the Throttle Body, its round, has to bolts holding it to the intake, and it too has a plug going to it. Should be fairly easy to find and clean. Hope that helps.

 

[Cavallo]

I cleaned my MAF on my 4.6, BIG differance!!!!

Just a cleaner safe for electric motors!!!

Some how it gets dirty, power was down.
I could not spin the tires in the RAIN!!!
Cleaned the wires and BAM!!! Tire spin from hell!!
This is on my F150!!

 

[1BadAzzGT]

It could also be the torque converter lockup schedule, remember this is an auto. Have you changed any of the programming with a chip or anything?