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5.0L (1979-1995) Mustang Technical discussions on 5.0 Liter Mustangs within. This does not include the 5.0 from the 2011 Mustang GT. That information is in the 2005-1011 section.

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Old 02-24-2013, 11:19 PM   #1
lavertue
 
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Vehicle: 1991 Mustang Gt
Location: Florida
Posts: 20
Default Car has terrible idle, boggy, and bad throttle response. (VIDEO INSIDE!)

Titles says it all, car has bad idle, boggy acceleration, and stalls out when I slow down fast. Also has terrible throttle response. Checked iac and it was working. Checked alternator and battery, they were good. Vacuum lines are all good. Fpr is good. I'm not sure what else to check. It has been running bad like this for a little while now. I just installed my new Walbro 255lph fuel pump and thats when it started doing this "surging" type deal. If anyone has any ideas on what to check, please let me know. Thanks again, LaVertue.


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Old 02-25-2013, 08:22 AM   #2
mustangsneverdie
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first thing I would check would be the check engine light, to see what codes you have
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Best time 13.7@ 102 mph 2.074 60' on street tires(in the '85)
Best time 14.3@ 96 mph 2.13 60' on street tires(in the '91)
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Old 02-25-2013, 08:54 AM   #3
mjr46
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check codes, check for vaccum leaks next and make sure there is no fuel pressure bleed down
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Old 02-25-2013, 01:41 PM   #4
mattdel
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Did you disturb or otherwise mess with the orange cap on the end of the return line when you installed the pump?
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Old 02-26-2013, 07:14 PM   #5
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How do I check the computer? I don't believe you can get it checked at Advanced Auto correct? And Mattdel, I did not mess with it. Thanks for the help guys!
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Old 02-26-2013, 07:47 PM   #6
rbowmar
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Yes, you can check your codes at most auto parts shops. Do you have fuel pressure in your fuel rails? That can help check all the different problems that can bedevil your fuel supply. I don't know if they loan them, but I bought a cheap one 5 years ago and it has saved HOURS of chasing possible fuel supply problems.
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Old 02-26-2013, 09:59 PM   #7
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Yes, you can check your codes at most auto parts shops.
maybe obd 2 equipped cars, but there isn't a vatozone I've ever goNE TO THAT KNOWS WHAT A KOEO/KOER test is for a ford much less has a scanner to run one. Heck you're lucky if they can even find the plug under the hood.
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Old 02-26-2013, 10:03 PM   #8
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maybe obd 2 equipped cars, but there isn't a vatozone I've ever goNE TO THAT KNOWS WHAT A KOEO/KOER test is for a ford much less has a scanner to run one. Heck you're lucky if they can even find the plug under the hood.
Yeah, I've realized that the people who work at auto parts stores don't know a thing about cars, very annoying. However, I tried to run the test myself with the paper clip and the plug under the hood, I couldn't get my car to flash the codes. Any ideas?
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Old 02-27-2013, 12:01 AM   #9
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I'm not sure if this is it, but I may be a complete idiot. I ruled out the one thing it may be without even testing it, the TPS Sensor. So I headed to the garage and popped the hood, and gave it a go. Well, I'm not even getting any reading on my meter. So, I figured maybe I wasn't getting power to it at all, but I pulled the plug out and tested the power supply and I'm getting power, just the sensor isn't registering that I'm getting anything when i test it that way. So I guess that means it must be bad I'm assuming? I'm going to go tomorrow and get a new one and see if that resolves the issue. I'll keep you posted.
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Old 02-27-2013, 06:50 AM   #10
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^^^^make sure when backprobing it: 1. your tapped into the correct wires and 2. your probes are making contact
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Old 02-27-2013, 06:50 AM
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