Well I got this 95 I bought running, it had a small engine fire and needed some wiring but all has been fixed now. The previous owner had the heads rebuilt before the engine fire and supposedly ran good. It appears they did a few mods, I noticed some under-drive pulleys, different exhaust and I thought I heard something about a chip so possible ECU work.The car runs real strong but down in the low RPM it bucks and surges a bit, definitely does it more with heavy load and in the lower RPM range, above 2K its pretty smooth but will still buck a little. Down below 2 it hates it if you give it more than 1/4 throttle, bucks etc. It has a new CTS, and a stock throttle body off another mustang with corresponding TPS and IAC, they seem to be working alright as the car revs clean and idle works decently. Oh and I think the PIP is good, like it said it runs clean in the upper RPM band and revs cleanly. Also plug wires/cap/rotor are brand new...
I do have a decent running 94 5.0 5spd car as well, and today I put the intake tube with MAF and IAT off that car on this one to see if it was a MAF problem. The bucking cleaned up a little but the car was totally flat, alot less power all over the place... and the bucking was only maybe 40-50% better (which may only be a result of the lack of power). So I'm wondering if the MAF that came with the car was tweaked for whatever mod(s) they did to it. Check engine light isn't on, and I know it works as I'd pulled the vacuum line off the EGR to test something and drove it and it lit it up....
On another possibly related note when the car bucks you can feel a clunky crunching in the chassis, sometimes feels like it's in the rear, sometimes trans, sometimes up front
. I had the car up in the air and was crawling all under it today checking mounts etc. Rear bushings etc looked good, trans mount looks good, motor mounts didn't seem to be too bad 
. I did find the passenger side axle has little bit of radial play, so bad axle bearing on that side but it wasn't way out . Took it to a friends trans shop and he drove it, he says he thinks the rear is trashed that the carrier/spiders/cross shaft is messed but I don't think it'd cause what i'm feeling. The rear makes no noise as far as whining so i'd bet the gears are fine and the limited slip seems to work well.I figure the bucking could be the motor or it could be the rear or trans binding.... but like I said it only seems to happen in the low RPM band
. Any ideas?
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