Hesitation in 3rd and 4th (please help!)
 

Hey guys... after about 5 or 6 minutes of driving I hit the gas or downshift to 3rd and give the car gas and it hesitates really bad. Bad enough to take it back home! This seems to be a low rpm problem, but when you drive normally in 4th (and 5th) it becomes a bad problem as well.
I put a 1" spacer (clearance problems) on saturday and that's when the problem started. We also connected some vacuum lines that were out of whack and I'm fairly sure we got it right. We thought it had a huge cam until we fixed some vacuum problems :p . I am wondering if it is the TPS because it now surges a little (throttle at 1000) and we took it off w/o adjusting it when we reconnected it. So if anyone has an idea I'm very appreciative! I think I'm at a loss until I can change or set the TPS at 099. But if that doesn't work... Thanks!

Re: Hesitation in 3rd and 4th (please help!)
 

Anytime we test something at the track, and have problems, we hit the big "reset" button. Put it back the way it was, and see if it goes away.

Set your TPS voltage (I'm not the guy to help with that, but there are several running around on here that can) and see what that does. If that doesn't fix it, yank the spacer and see if that fixes it.

Sounds to me like ya got yourself a vacuum leak. Good gaskets on BOTH sides of the spacer? Torqued down properly?

This is an easy fix, we did "this" and the car started doing "that". Well, "this" is your problem. It's something you guys did to it when you put that spacer on. Check/set the TPS first.

Re: Hesitation in 3rd and 4th (please help!)
 

this article has 5 parts/pages, one of them is resetting TPS, good info

http://www.muscularmustangs.com/iac.php

Re: Hesitation in 3rd and 4th (please help!)
 

Kewl- thanx guys.... anyone got a Vacuum diagram? The one off of autozone.com is really hard to read! :eek:

Re: Hesitation in 3rd and 4th (please help!)
 

this has every diagram u'll ever need.....then some! when you see tmoss on this site tell him that he's the MAN!!!!!!!!!

http://www.veryuseful.com/mustang/tech/engine/

Re: Hesitation in 3rd and 4th (please help!)
 

Yes sir, that's me drooling- Hey I might even get my a/c working right again now!

tmoss - you the man :D

Re: Hesitation in 3rd and 4th (please help!)
 

http://members.tripod.com/sparkplugs/idle.htm

Do that first.

Re: Hesitation in 3rd and 4th (please help!)
 

Adjusted the tps and drove it for 5 minutes... started again- the thing hesitates and exhaust starts sounding crappy. I think it may have backfired. I'm going to check the timing, considering when we unhooked some of the vacuum lines and one back up and inserted a little 1 1/2" threaded grommet back into the back of the intake the car quit "Camming" and ran smooth. The idle was then up to 2000 rpm so we backed it down. That is when I started having problems. The vacuum lines look ok to me though?
It does have the egr eliminated and the smog pump eliminated. So much for the track tonight!

Re: Hesitation in 3rd and 4th (please help!)
 

When you set the TPS voltage did you set the idle first.

Unplug the IAB and set your idle, set your TPS voltage , then hook back up the IAB and turn off ignition and disconnect the neg battery for @15 min to reset the EEC.

Might have to do this a few times.

Curious if your TPS voltage changed from where you just set it.

Re: Hesitation in 3rd and 4th (please help!)
 

Thanks I'll try that- but my friends are starting to suspect my pickup coil in the distributor. We checked my timing and when I hit the gas it advanced and retarded. I changed the control module which tested to be bad and we think the pickup coil may be to blame. I'll have to buy a pickup coil before I know this to be true. So evidently it's doing this all the time and is only noticable under heavy stress... I hope this works- I still have got to change some hoses around the thermostat where it started leaking. It would be nice to see what she'll do at the track!

Oh yeah I did a tune up as well-

Re: Hesitation in 3rd and 4th (please help!)
 

I agree with Jester, I would suspect a vacuum leak. That was the culprit for me 2 weeks ago when working on the buddies 408w.
Ryan

Re: Hesitation in 3rd and 4th (please help!)
 

I'm beginning to think Jester (which btw was my c.b. radio name for years- could choice!) was right in the first place- going to buy 2 more gaskets this weekend -I just remembered one had a crack, but on the outside of the screw. I guess it could have more considering I have a whining noise coming from the intake somewhere. As well as a pickup coil, coil, thermostat, etc...

This might take a few beers to get right.

Re: Hesitation in 3rd and 4th (please help!)
 

Finally! After 2 weeks of tinkering we found it... Fuel Pressure Regulator. It seems the 1" spacer was too much air for me. I have it almost right, she still sputters a little in the exhaust. I think she's a little rich now.
BTW, the spacer gasket was bad... along with the TB gasket, talk about vacuum leak! Now onto the impossible shifting...

Thanx guys!

Re: Hesitation in 3rd and 4th (please help!)
 

Scratch that, I turned it down half a turn and she started again... I don't think that 1lb difference should have caused this. I'm gonna try it with it turned back up. There are now 2 of us with this same problem.... :mad:

http://forums.mustangworks.com/showthread.php?t=46834