car still has rough ide and motor bucks horrible

[Lifted04FORD]

hey guys

i just bought my 92 TSI AWD. 144k miles from orig owner. its 100% stock

It was running really bad when i brought it home so i changed wires, plugs, oil ect.. still horrible

so i built a boost leak tester today.. fixed all leaks.. started the car up.. idle was fine around 1000.. after it warmed it dropped to around 600..

It sounds like the car is only running on 3 cylnders..

so i take it for a test drive.. and anything below 3000-3500 without boost the whole car shakes the motor bucks so hard... i dont know what else to do.. someome please give me some advice!!!

 

[Kloopofadown]

You should check that the MAF sensor doesnt have both honeycombs removed from it.

 

[Artago]

Have you checked your cylinder compression yet? Could have a bad piston ring. -Tom

 

[Fayt]

Do all basic maintenance to the car if it hasn't already been done.

Check the turbo for any shaft play or leaking.
Check boost leaks and compression test it.
Make sure your MAF is in good condition. Swap it out with a friends if possible.
Look for worn couplers that may leak when under load/flexing.

 

[bob123131]

After all the basics Check to see if the timing belt has been changed. It sounds exactly like your balance shaft is out of phase which happens alot when noobs do belts. I know becasue i did it once.

 

[spyderturbo007]

You might also want to pull the ECU and make sure the caps aren't leaking. It's a common problem with 1g's and an easy thing to check.

 

[Lifted04FORD]

well guys here comes the bad news... compression results 150 3 135 145

I just bought the car 4 days ago

 

[Artago]

yeah there's your problem... you need a rebuild with new rings and maybe pistons too... sorry to hear that...

 

[Lifted04FORD]

well i pulled the head off... and found a huge hole in the valve. thats why i was getting low compression... the piston looks fine along with the wall