'95GT hiccups @2000rpm under load... help...

DavidBoren · Oct 9, 2014

Car is a 1995 GT. Full exhaust and cold air intake have been on it for about a year now. Car still has less than 100k miles on the clock. Engine is stock, tune is stock. Car has 3.73's and 315's out back.

Anyways, while accelerating, as soon as it reaches 2k on the tach, the car hesitates. There is no backfire associated with this condition. It can be revved past 2000rpm while not in gear and the car doesn't hiccup/hesitate. So it only happens while in gear, driving with/under load.

Cleaned the MAF. Made sure everything is hooked up like it should be. Filled the tank with some premium fuel. And added some injector cleaner and water remover just to be safe.

The car accelerates fine past 2k. No other symptoms exist. Just a small hesitation at 2000 rpm's, and I am not sure what it is. From what I have heard, it could be a faulty MAF or O2 sensors, or both. Also thinking it could be related to the TPS. Not sure what it is, but I don't like it. Any help would be greatly appreciated.

the5.ohh · Oct 9, 2014

Check your O2 sensors, plugs, wires, fuel filter.

CC'S95GT · Oct 9, 2014

I'm thinking coil. procedure for testing it is in your haynes manual.
bad TPS is usually assoiciated with a hanging idle

toyman · Oct 9, 2014

I wouldn't be too quick to eliminate the TPS.Confirm the voltage sweep being smooth from closed to WOT (KOEO). Absolutely no pause or hesitation as the throttle is opened.

Phoenix0783 · Oct 9, 2014

Check tfi module. I had the same symptoms when I had my '94 and it turned out the bushing in the bottom of the distributor was worn out causing the timing to advance under stress.

CC'S95GT · Oct 10, 2014

Phoenix0783 said:
Check tfi module. I had the same symptoms when I had my '94 and it turned out the bushing in the bottom of the distributor was worn out causing the timing to advance under stress.

The TFI module is mounted under the air box on the r/h fender apron. The PIP is what is inside the dizzy.

5-oh-MUSTANG · Oct 10, 2014

Ive read a bad egr valve can cause this.

Phoenix0783 · Oct 10, 2014

CC'S95GT said:
The TFI module is mounted under the air box on the r/h fender apron. The PIP is what is inside the dizzy.

I wasn't talking about the pip, I was talking about the actual shaft inside the distributor. Also, the pip is not inside the distributor, it's by the air box.

CC'S95GT · Oct 10, 2014

Phoenix0783 said:
I wasn't talking about the pip, I was talking about the actual shaft inside the distributor. Also, the pip is not inside the distributor, it's by the air box.

WRONG!!! PIP stands for Profile Ignition Pickup. IT IS INSIDE THE DISTRUBUTOR! The part that is attached to the shaft inside the dizzy under the rotor is a reluctor wheel.
AS I said the first time, the ICM is on the r/h fender well.

Phoenix0783 · Oct 10, 2014

CC'S95GT said:
WRONG!!! PIP stands for Profile Ignition Pickup. IT IS INSIDE THE DISTRUBUTOR! The part that is attached to the shaft inside the dizzy under the rotor is a reluctor wheel.
AS I said the first time, the ICM is on the r/h fender well.

OK, the actual module is inside the dizzy. I meant the thing you unplug to do the timing.

CC'S95GT · Oct 10, 2014

Spout connector? Also located on the r/h fender by the air filter

Phoenix0783 · Oct 10, 2014

CC'S95GT said:
Spout connector? Also located on the r/h fender by the air filter

That's it

DavidBoren · Oct 10, 2014

Thank you all for the replies. I will certainly pass this information on to Tyler. I am thinking that it is or has something to do with a computer controlled system. It is consistently at 2,000rpm. No more, no less. And only under load. It seems that something physical would affect a broader range of rpm's. Thanks again, I will make sure Tyler checks the above mentioned areas.

DavidBoren · Oct 10, 2014

Also, what, exactly, would go into checking the tpi/spout connector? You said where it is, but what do you look for when checking it for proper operation?

CC'S95GT · Oct 11, 2014

The spout connector is just a jumper. When removed for setting base timing, the computer no longer controls ignition timing. With the timing light you'll be able to clearly see what the timing is (usually 10*-14*). With the spout in, the timing will be all over the place, if you could even read it.
The engine will start and run fine with the spout out up to a certain RPM then it will run out of advance.
Every year when I get e-checked I'll pull the spout connector just around the corner from the shop then drive it the last 1/4 mile to the shop. With the spout in the car will barely pass the sniffer but with it out, it passes with flying colors.

5-oh-MUSTANG · Oct 11, 2014

CC'S95GT said:
The spout connector is just a jumper. When removed for setting base timing, the computer no longer controls ignition timing. With the timing light you'll be able to clearly see what the timing is (usually 10*-14*). With the spout in, the timing will be all over the place, if you could even read it.
The engine will start and run fine with the spout out up to a certain RPM then it will run out of advance.
Every year when I get e-checked I'll pull the spout connector just around the corner from the shop then drive it the last 1/4 mile to the shop. With the spout in the car will barely pass the sniffer but with it out, it passes with flying colors.

How does this help with emissions? Don't you have cats anyways? Wouldn't you be fine with it in?

CC'S95GT · Oct 11, 2014

Yes I do have cats but it just barely passes even with the cats. So to avoid stressing I just pull the spout.
I don't really know why this works like it does. I learned this this trick from a fox mustang guy.
I bet it would pass with a o/r mid pipe.

badsheep5.0 · Oct 13, 2014

First off think you davidboren for looking into this on the forum while I juggle some new things in my life along with getting my car back to it's full running self hopefully Tuesday it will be back to it's self here is a pic by the way way of the car he has been talking about although being a pain in the ass I still love it

DavidBoren · Oct 14, 2014

Distributor is shot. Vacuum line is leaking. And the pcv valve is junked. So, not only was it just one of the things that can cause these symptoms, but it was all of them, combined, at the same time, in a row. Guess what Tyler and I are doing this weekend...