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Discussion Starter #1 (Edited)
changed out Egr valve and diff pressure

.changed out EGR valve and diff pressure sensor ,4.6 engine still sttutters under accell on my 95 T-Bird,hooked up code reader ,no codes came up ,any idea's?
 

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EGR won't affect acceleration unless it's seriously stuck open. I'd be cleaning the MAF, making sure you don't have any vacuum leaks, and doing a tune up if it hasn't been done in at least 50,000 miles.
 

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Discussion Starter #3
has fairly new plugs and wires also checked for vacumn leaks and replaced any hoses that were deteriorated,it idles at about 650 rpm. I will clean the maf and see what happens.
 

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Just for clarification, when you say stutter, you mean misfire? Or do you mean hesitate?
 

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Discussion Starter #6
it feels like it is misfiring ,like the timeing is retarded or somthing.it does that for like 4 or 5 seconds then takes off ,it usually happens at ,low rpm in high gear when it has to lug a little.
 

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Hard to say without actually seeing the car. Need to hook up a scan tool ( not a reader ) to look at live data and see what the computer is actually reading. Code reader will only show a code if its passed the threshold for failure parameters. If you can get a code, and your tool has Freeze frame data, that would help a little but not as much.

For example .. I just got a 95 Toyota in that had a P330 code ( knock sensor ) - has nothing to do with emissions. The car also hesitates on acceleration which was their main concern. So I checked it with the scanner and the fuel trims are up to 29% on bank 1, 26% on bank 2 .. has a pending code for fuel trim malfunction on bank 1 (P0170) - once it goes up to 30% on either bank it will throw a P0171 or a P0174 - I would expect to see both but until they get to that 30% it wont throw the codes I am expecting, but reading the long term fuel trim told me right away ( vaccum leak ) .. so when I popped the hood and found the intake tube was split in half, it was a no brainer.

With OBD2 vehicles, you can pretty much diagnose the problem before you even pop the hood to look around if you have a tool capable of reading live data instead of waiting for the codes to show up.
 

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Discussion Starter #8 (Edited)
cleaned the maf ,wow was it dirty the sensor wires were coated with a black soot looking material,it runs a heck of a lot better,still to early to say all is well ,need to drive it more.I just purchased a Actron CP9145 scanner online , can't wait to use it.
 

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It sounds like a MAF or a vacuum control issue to me. Heck, maybe even a throttle position sensor issue.

Edit: Looks like cleaning the MAF may have helped you out on this one.
 

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yeah, i had the same issues with mine when i drove her off the chevy lot in columbus... fell on her face under accel for a few seconds before finally getting up and moving(still slowly)

they had no idea what they were doing, pressure washed the engine down and didn't touch the MAF, fuel filter or anything else common to fail on cars >.> they also put a non backflow ACdelco filter on it.... knock knock knock anyone?

anyway, needless too say, after i payed too much for her, i dried out the motor... cleaned the MAF, changed out the fuel filter, plugs and wires, and she ran like new.

and i just changed the wires and stuff for [email protected] and giggles. ran great after the $3 can of MAF cleaner. :D
 
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