View Full Version : Help: Now power above 3psi

08-11-2003, 04:18 AM
A friend of mine just bought a pertty nice 90 35th anny 5speed. When he got it, it had a real problem of a serious bucking when you hit about 4psi of boost in any gear. We changed the fuel filter (just the start of a tuneup) and it fixed the bucking trouble, but then comes a mystery.

The boost gauge peaked aruond 13psi of boost but above 3psi, the car pulled worse than an N/A v6. What could be causing this?

We're going to be changing the plugs in the morning (yay!....no...not fun) along with the oil and air filter (which is almost solid black). We're also going to pull the IC out and clean it out real good with gasoline to make sure there's no oil inside it.

Any other tips of things that could be the cause of no power or other things to do in this general tune up? We may do wires after the plugs, funds providing, but could bad plugs/wires cause this total loss of power?

FearThis SC
08-11-2003, 09:12 AM
Change the plug wires!


08-11-2003, 10:32 AM
Don't use Bosch plugs, use the OEM plug.


08-11-2003, 05:39 PM
Well, being a V8 guy, I've decided I don't like SCs anymore. Too much of a ~~~~ when they get in a bad mood. :D

Anyways, I crawled under it today with the hopes of doing the plugs...I have NO CLUE how you guys change your plugs. Any advice on that, I plan on having a local SC buddy come over to do these, along with wires as well.

But the 4psi bucking has returned. We noticed that the vacuum line that hooks into the intake tube before the TB was undone so we hooked that back up. Afterwords, it only hit about 11psi of boost and after a few miles, the bucking returned. Oh yeah, we replaced the air filter at the time too.

Any insight into this violent bucking and other problems? Could serious boost/vacuum leakage cause all this? The bucking, the lack of power, etc.?

08-11-2003, 05:50 PM
The problem you are having is because you have bad plugs and wires it is very common and only gets worse. Before you know it it will start bucking at 10 in/Hg.

You can get the plugs more easily from under the car. Run it up on some ramps and you'll be fine. Do a search for bucking or spark plugs you'll find what you need.


08-11-2003, 06:00 PM
Yeah, sorry if I seem like an idiot, I just don't know much about the SCs, I'm a 4.6 guy. But yeah, I feel like a bit of a dipstick because I just searched out "bucking" and found several threads that describe everything exactly.