• Hello there guest and Welcome to Fox Body Mustangs forum, This forum is intended to be used by enthusiasts of the Fox body Ford Mustangs (1979-1993)!
    To gain full access you must Register. Registration is free and it takes only a few moments to complete.
    Already a member? Login here then!

Hesitation under acceleration

87_notchfox

just another notch among the rest lol...
With in the last day my car started to hesitate under acceleration. Not sure why got new cap, rotor, wires and CAI. The car files fine but like I said stumbles when I gas it. I got a new fuel filter just got to put it in...anyone ever experience this n figured out wat it was?

Sent from my LG-D800 using Tapatalk
 

Blown347

Moderator
Staff member
Check all the obvious stuff. first would be the MAF connector. if its not fully inserted that could cause this, next is plug wires on the exhaust if one burned through resting on the header or something. Check TPS voltage with engine off key on Run.

Start with these things. could also be the TFI module, especially if its factory original.
 

87_notchfox

just another notch among the rest lol...
Checked da wires there good plus I bought the boots for them so they looked fine. I'll check da MAF connection. And the TFI module did cross my mind. Because it does miss when the car warms up

Sent from my LG-D800 using Tapatalk
 

Blown347

Moderator
Staff member
Yea thats how mine was, it would only start screwing with me when the car was warm and the module was obviously getting heat soaked. mine eventually started to stall on me for no apparent reason though. i bought a durmast TFI and was done with it.

If anything, you could buy one (like 45 bucks i think), install it and if it doesn't fix anything then just return it lol.
 

87_notchfox

just another notch among the rest lol...
I thought about that because while it's cool it runs good no issues. Gets warm n it misses under acceleration so I think it's starting to go bad. I will look into it tomorrow about getting a new TFI module and I hope that's it

Sent from my LG-D800 using Tapatalk
 

Blown347

Moderator
Staff member
and double check the TPS voltage because if thats too far out of spec it can cause similar conditions
 

87_notchfox

just another notch among the rest lol...
Yeah I got to check that also because some times it dies out when m driving n I step on day clutch. But I thought that could be because of the IAC valve

Sent from my LG-D800 using Tapatalk
 

FoxBodyMustangs

Administrator
Staff member
With in the last day my car started to hesitate under acceleration. Not sure why got new cap, rotor, wires and CAI. The car files fine but like I said stumbles when I gas it. I got a new fuel filter just got to put it in...anyone ever experience this n figured out wat it was?

Sent from my LG-D800 using Tapatalk
@87_notchfox which CAI did you get?
 

87_notchfox

just another notch among the rest lol...
I got a summitracing 75mm but m waiting on the pigtails to put it in...because right now m running a stock one with a 70mm body
6eryzaga.jpg


Sent from my LG-D800 using Tapatalk
 

Blown347

Moderator
Staff member
@Blown347 hey bro my tps is fixed and has no adjustment to it. Its on a 70mm acufab TB

Sent from my LG-D800 using Tapatalk
Yea but it's still a ford TPS right? You gotta check the voltage and if it's wrong, take a small file or drill bit and oblong the screw holes in the TPS to be able to turn it and get it right. It should be <1 v (many people say the magic number is .99v, but as long as its between .8-.99v, the computer will take care of it)
 

Blown347

Moderator
Staff member
If you've never done it, just probe the green signal wire and ground to the throttle body bolt with the key turned to on.
 

Blown347

Moderator
Staff member
If you loosen the screws it should be able to move a tiny bit as is. But usually if it's not in the right range you have to oblong them to turn it enough.
 
Top