Hey guys, Thought I'd leave a post here too and see if anyone has an idea. Need some help here. Just bought my first mustang two weeks ago. Shes a '02 sixer convertable with 38k miles. Always stored with a cover over her and indoors to boot so she looks great still. Didn't notice any issues during the test drive other than you feel every bump in the road through the suspension.
So the day after I bought it, I noticed that while accelerating through 30-45 mph it started jerking/surging. Felt like a really bad transmission shutter. Mechanic swore up and down that it was something simple so I replaced plugs and wires with the premium stuff, swapped the air filter and fuel filter, and had my mechanic clean the throttle body and air flow sensor. That helped it to an extent (took it from about a 10 to a 7 on a 0-10 scale). She idled much better though.
My mechanic still swore it wasn't trany related. He checked some engine codes (though no lights on) and found the EGR valve pressure sensor was out of spec. He swapped that out and it seemed to fix the issue! I was thrilled! Drove it around that night and it was fine. Then I went and put gas in it (speedway 87 octane), got a block down the road and BAM it starts it all up again. It started shuttering really hard during acceleration at the speeds listed above. My mechanic was stumped. It sounded like he had lost his patience for the issue and didn't want me to bring it back.
So now I'm trying to figure out what to try next. The mechanic said that driving it wont hurt it, just annoy the hell outta me. I put 5 gallons of 93 octane (BP brand) in it last night and it seems to have calmed the issue for the time being.
Any ideas? And what grade of gas do most people run in the V6 models?
Thanks for all your help fellas!
Paint