Surging???? what is it!!!

[SHOguy 92]

Well, I'm currently trying to figure out the surging in my 91 SHO. I just clean out the IAB, put on a new TPS sensor (that seems to help). I'm thinking it might be the soleniod that attaches to the IAB? I don't know if thats common for them to go. But here's how it acts. A few nights ago I was cruising with some friends on the freeway as I hit 5500rpms in 4th it's like it was rev limited right there. Would not go over that???? At steady throttle it doesn't have a problem, like if I'm going 55mph or just going down the freeway. Most of the problems seem to be in the beinning of 1st gear and beginning of 2nd gear, but sometimes the very top of 3rd and 4th? I got no CE light coming on, so has anyone expirenced this before?

 

[DigDeez]

I think I ran into similar issues when I replaced my TPS. Are you idling higher than normal-say above 1K rpm-in park? I can't get too technical about this for lack of tech knowledge but I was told that the voltage on the new TPS is out of spec. Maybe someone can post as to how to rectify the voltage! What I did was purchase another TPS (a cheap part) and the surging went completely away. Make sure the product number of the TPS matches up with the original Ford TPS part # for your SHO. Reset your idle may help also! Hope this helps.

DigDeez

 

[inverse1216]

hey shoguy, any luck getting that surge to go away did u take any of digdeez advice? im askign cause im having the same problem with my 93 beginning of 1st and 2nd gear it hesitates b4 it gets power. thanks

 

[SHOguy 92]

nope wasn't my TPs, could be yours though.

 

[Hack]

Hows your crankshaft position sensor?

 

[inverse1216]

shoguy, did u ever figure out what it was?

hack, idk who the question is intended for but as far as i know mine is ok, there a way to check it? no ce light is on if that means anything. in all honesty i think its the fuel pump going.

 

[inverse1216]

hey guys i hope this helps but i was doing some experimenting and i came across some stuff. i had put in a sho shop induction tube (home made) prior to the surging happening i had the IAT sitting on the side and not in the air flow path. soon after i noticed that upon start up the car would drop in rpms almost dying and then would hesitate after shifting into each gear. well this weekend i decided to put my stock intake system on to see what would happen and to my suprise the surging went away and there was no hesitation after each gear.

im only posting this to see maybe those of u that have the same problem could be a cause of the intake if u have a aftermarket intake. i also was wondering did u guys have to have some changes made to the computer for the intake? ill be putting the custom intake back on but including the IAT and see if that cure the surging. hope this is some what helpful.