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Random sluggish problems

801 Views 9 Replies 3 Participants Last post by  sloww2v
I have a 1996 mustang, originally a v6, it was swapped with a gt motor and everything needed to be a gt before I bought it. Well anyways, recently I have noticed at times, literally randomly, the car is really sluggish. It seems so slow to rev between 2000-4300 when suddenly at 4300 it seems like the rev limiter kicks in. It will not let me pass that rpm and the acceleration and shifting it just so slow. But yet some days it acts normal. Revs normal and quickly like it should, power all though my rpm range, I can actually hit my redline shy over 6000 rpms, acceleration is great. Before I bought it the guy just had the automatic transmission rebuilt. He says it might be a electrical problem or connection somewhere and I do agree with him as just don't have any idea where possibly? I'm new to the forums so sorry for the huge post. I just want to get it figured out because I can't have fun in my pony more than half the time due to this problem. I've had it start slow and sluggish from say a light and all of a sudden it will be normal and quick again to it being the opposite, starting normal and quick to going absolutely slow and sluggish. I have a small exhaust leak that gets much louder when it sluggish and the throttle response is terrible vs when its acting normal. All help and suggestions are highly appreciated thanks.
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I also forgot to mention sometimes the car will randomly surge. Like if someone hit the gas and randomly too, only a few times with this but the car will suddenly start sounding like its cammed and runs extremely rich and wont shift gears unless I throw it down into gear labeled 2 and it goes away.
When was the last time the fuel filter was changed?
I'm assuming about a year and a half ago when they swapped the pumps.
Any codes? Double checked vaccuum leaks? There are simple things you can do to rule stuff out. Fuel filter (like mentioned above) should be changed, cleaning the MAF.

Is the battery and alternator working properly?

What is the fuel pressure with Key on/Engine off? When engine is running?
Codes are for the O2s but I have a off road h pipe so I can see that. Occasionally the code for MAF and tps sensor communication comes up and something about max engine speed reached which I'm assuming thats why it doesn't let me pass 4300 rpms. Cleaned MAF recently and didn't help. Battery is new and no problems with the alternator. Doesn't seem to have vacuum leaks but not sure about the fuel pressure. Someone told me its a chance it could be the ecu?
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I will try the fuel filter next payday.
Today passenger in my car accidentally kicked the area where my ecu is by the door, the idle surged so i tried it again and it also surged when it hit it. It seems to be hitting one of the connections. Could this be my problem?
Only one connection when I smack it makes the car surge in idle. Could this be the bad connection causing my problems?
Turns out its the ecu. Gonna just go to the scrap yard and pick up one with matching numbers.
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