05_stanger_gt

I have a 05 gt. My problem is its running like crap. When I first got it (about 3 weeks ago) it ran like a champ only did it a couple times. But now it's everytime I drive it.

When the motors cold after cranking it after sitting over night or all day it runs like a bat outta hell. But after driving it a while an the motor warms up when taking off its falls on its face until I get my rpms up. I can take the car outta gear an wrap it out no problem. It's like I put it in gear an it lugs, spits sputters backfires. An it does it everytime I shift or when I rpms are lower than about 2grand or 1500. Iv been doing my own work on my vehicles for the past 7 years an never really had a problem l fixing my problems. But this has me stomped.

It doesn't throw any codes, except for the fuel neck seal. Other than that it shows nothing else. I'm trying to get second opinions on it before I go dumping a bunch of money into stuff that's not a problem. I run premium fuel, an royal purple oil. It's what the guy before me ran. P.S.- this is my first mustang iv owned. Iv always wanted one. An I wanna build the car for a toy but wanna fix all issues first. Any help would be greatly appreciated!!

movielover40

How many miles are on it?

Have spark plugs ever been changed?

05_stanger_gt

140k from what the guy I bought the car from says the instrument cluster needs to be changed. But so far I haven't messed with the plugs yet. I did however change the fuel filter about a week ago. Didn't seem to help much.

All4One

My money is on plugs, wires, or distributor cap. You can pull one wire off the cap at a time while its running and see which one doesn't drop the cars power. That would be the one not working.

Also, you posted this in the "forum issues" area, so you may not get as much visibility on this post.

99GTvert

Moving to tech..

danzcool

With a 2005, there is no distributor, electronic ignition. But following his logic the COPs (coil-on-plug) may be starting to fail.
Also cleaning the throttle body and MAF wouldn't hurt.

Otter

Would do that first and see what happens..20 minute job

Ford-a-tude

Welcome to the exciting world of Mustangs! I would agree with what has already been suggested. Basically you need a tune up before evaluating any issues. What got my attention was you said it runs well when first started but then falls flat when warmed up. Keep in mind when these cars are first started the computer is running fuel and timing based off default tables in the tune. After the engine temp rises to normal and the oxygen sensors are warmed up it will switch from the default values to the live data coming from various sensors like the O2 sensors and the Mass Airflow sensor. If one of those sensors is bad or borderline it may affect performance yet not trigger a check engine light. At 140k you can expect to clean sensors that get dirty like MAF and replace those that wear out. I kinda put my money on the O2 sensors. If you do not know the history of the vehicle be very careful changing the spark plugs. If by some chance they are still the original ones there is a good chance you will break them trying to remove them. Search the forum for spark plug breaking, there is a lot of information regarding this known issue.

flash_xx

Change the O2 sensors and clean the MAF with MAF sensor cleaner, don't use carburetor cleaner or any other solvent. If it were the coils or sparkplugs it would sputter all the time, not just when hot.