Engine New To 94' Cobra, Seeking General Advice On Performance.

Just picked up a 94 Cobra. It has 33k miles on it. It was a one owner car, and the guys baby. With that being said, it was used for car shows, small town cruises and such. Drove it from PA to MS. Not a bad run at all. Only issue was a CEL during accel or deccel, which seemed to clear up the more I drove it. Got it home, replaced to rotten purge valve lines, to get rid of the gas fume smell. Cleaned the MAF and AIT while I was in there.... So... Now...
It has a hang idle, which it had before I did everything, i was hoping to fix it. It also has a nasty hesitation, if I'm sitting and I hit the gas, to rev it up, it kinda hesitates(chokes) then the rpms go up, and slowly..trickle..back down. If I'm driving, and let off the gas...It starts to engine brake, for a sec...But then it kinda, really starts to engine brake even harder(hope that made sense, lol).
I used to own a 02 GT 4.6L manual. It snap revved a lot faster...not sure if this is just a 5.0 characteristic or not... Please enlighten me on the 5.0. It has a bright future with me, just slowly getting there. Thank you in advance for any help/advice on what little trucks and stuff to fix and "mod" on it. Had a lot done to my old one, want to get this one there, and beyond it.

No one?? Nothing?

RaggedGT said:

Welcome.
Post pics when you get a chance.
The info you gave is kinda basic,so my recommendation is to start with the basics lol
With such low mileage im guessing that car has had minimal maintenance- i.e spark plugs,wires etc.
I'd pull a couple of spark plugs and inspect them. Check the gap.
Look over the plug wires,the cap and rotor.
Clean the throttle body, clean the maf.
Verify timing-give it the works lol
I'd also search this site for @jrichker , he has a 'Surging/Hanging idle' checklist posted a few dozen times,very informative and should help you sort this problem out

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It has actually had, A TON of maintenance, lol. I have all records from the day it was bought until now. Last plug change was last year. I mean yes they could be bad, and I'll get on checking that. Thank you!! I'm new to the 5.0 world, built several 4.6's(99-04) tho, lol
I'll check those sites, and do the idle reset procedure. I'll keep everyone updated.on the sticky.

How do you post pics? I tried, but it wouldn't let me upload from phone. I'll do a search to see if it's in the forums.

jrichker said:

You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. It includes how to dump the computer codes quickly and simply as one of the first steps. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.

It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 200,000 hits, which indicates it does help fix idle problems quickly and inexpensively.

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See it's not surging, it just hangs for a few seconds instead of the rapid decrease I was used to in my GT. I wasn't sure if there the idle reset will fix it or not. It idles great, just hangs after a free rev and between shifts. I'll still try just to see. Not sure if it was a different cause or not. That's all. Thank you tho, very much! Any and all help is welcomed!!