Odd Problem...should be easy...but?

[nomadrider]

My car is a 2003 Mustang V6 (Pony Package) with 120,000 miles on it. We bought it new. It runs OK when you first start it. About a minute later it will start to idle rougher Sometimes it even stalls. As you drive away it will run good and then suddenly chug chug and then good a again. This weird chug chug will happen until it warms up and then the car runs good. As long as it stays warm it runs good. Go in a store and come out, chug chug until it warms up.

It doesn't throw any codes. I even brought it to a local garage and he put it on his equipment (all I have is a code reader), no codes. After this problem started I have changed the plugs, plug wires, power steering pump, water pump, and idler pully. This has me stumped...seems like I am just over looking something.

Help

 

[ThatBear]

I've never owned a V6 but that sounds like a problem one of my Fox bodies had. I replaced the temperature sensors and it went away. As far as I could tell until my car warmed up the ecu was dumping a ton of fuel into it and kind of bogging it down like you're experiencing, except mine would backfire through all the gears until it warmed up. Its worth a shot to check them, they're relatively cheap

 

[JB04v6]

o2 sensor test w/ digital multimeter at 1 volt pos to probe neg to body etc

 

[03 V6 stang]

My car does that chug chug action once in a while. I think its my fuel pump because when I felt my car start chugging I saw my low fuel light turn on and turn off really quick. So I think my fuel pump is going bad. My car only chugges when im cruising at a constent speed for a little bit, but it only happens once every 2 months.

 

[JB04v6]

were you also low on fuel. it suck water and contaminants when low. i cured a weird acting one by 2 bottles water remover, nt getting gas when tanker filing and gas level kept up. my 04 v6 even told me my gas cap was off/loose once and it was when i checked. a closed system fuel pump o ring leak causes problems and ya have a pain troubleshooting. check if there's recalls of that year model and also look up " service bulletins " because the mechanics keep up to date rather than guess. easy to unhook fuel filter and pump to glass jar and see the fuel quality when at low level. bulletins are my first pick, ya get dirty and frustrated just guessing

 

[g96v6-250k]

I would guess injector issue but i'm probably wrong. if have a volt meter check for big voltage drops. should hold around 13-14v fairly steady when driving. use a meter on the cigar lighter with a old air pump wire.

 

[SILENTPANDA25]

fuel filter or clogged fuel injectors