Charged Stang Hesitating or Missing on hard Acceleration

[AllAboutSpeed]

Hey guys a week ago i noticed that when I stab on the gas in my charged GT it seems to miss. The odd thing is that i can roll into the throttle and its fine.. but if i floor it around 3k it seems like the motor just cuts out and sputters. Othertimes it pulls hard till 4.5k and it acts up.

Now to throw some possible unrelated info in or possible just a coindence but sometime last week before i noticed the problem i did some monkeying with my ac clutch and took out a spacer to engage the ac better.. since a few weeks previous to all of this i had to replace the ac clutch and i guess i had to many spacers in because it wasnt blowing cold.. so when i took out one spacer the ac now blows cold.. I also noticed tonight by AC lines were sweating bad and i could hear the water from the ac dripping on the headers... yet i didnt have the ac on, since its only 50 degrees out.. For any reason could the ac just be engaging slighty and causing my car to miss??

This is about all i can think of. The car was tuned a month back by DynoTune MP and didnt have any problems untill now.

 

[stangman]

to start off, clean the IAC

 

[AllAboutSpeed]

to start off, clean the IAC

I will do that in the morning..


Could plugs be a possibility??

 

[stangman]

it's a possibility, but the IAC is alot more likely. if it were me trying to find the problem my progression would be:

1- clean IAC
2- clean MAF
3- change plugs
4- change fuel filter

 

[Shiroelex]

I'm going to say a bad COP, as my first guess. Second guess being a fuel starvation issue, like a clogged filter, or inadequate/faulty pump. The A/C compressor will run if you have your defrost on, as well. If you turn the blower off in the car and set the vents to off, the compressor should never run, and the lines should stay ambient temperature, and dry.

 

[AllAboutSpeed]

well i took it back to DynoTune MP and we found out why it was hesitating. When I added the charger I never went to colder plugs and left the originals in. Which were Motorcraft platinums.. It blew the gaps way off due to the colder weather... they were at .055 so we put in some NGK's and the hesitation was done. However on the dyno im now 45 HP down through the entire rpm range and am running a 12:1 vs 11:1 fuel ratio as I was before. They told me that I must have a bad coil pack as well.. Does this sound right to you guys? and does anyone know how to test the packs so I dont have to buy 8 of these suckers and 45 a pop. Thanks

 

[GodAmGT00]

Well, you could do it like the "primitive man," and disconnect each one when at idle. If the engine stumbles, then that coil is good. If there's no change, then you my friend, have found your malfunction..

I'm not sure how the shop manual does it, probably by measuring resistance across the COP, but what do I know??



JT

 

[AllAboutSpeed]

Well, you could do it like the "primitive man," and disconnect each one when at idle. If the engine stumbles, then that coil is good. If there's no change, then you my friend, have found your malfunction..

I'm not sure how the shop manual does it, probably by measuring resistance across the COP, but what do I know??



JT

Well I went ahead and pulled the plugs and coilpacks. All the plugs look identical in color. However when i pulled one of the plugs out it had some electrical tap around the threads. Actually like a big 2" chunk. It appears that it may have come from the wiring harness above. I dont know if it would matter but say because of the tape being there.. could the plug possible not have been all the way in the head, causing a possible 45hp loss? I know it was tight.. but im thinking the tape may have not allowed it to be fully in..

I than checked the resistance on every coil and they are all about even. I also started the car and disconnected a coil one at a time and you could tell a drop in rpms on each one i did.

Im stumped.. The car feels fast now.. but I guess im just worried im still not at the normal level. My g/f said it feels faster since i took the plugs out and took the tape off.. but than again who knows. I just dont know how i could lose 45hp if the plug was spaced out less than an 1/8" out.. Does this make sense? Its hard to explain