Hey everyone,

I haven't owned my FD long and I've run into my first problem. When cruising at partial throttle at around 30mph or 50 kph the car starts to buck a lot. Its like the power completely drops off then comes back a few seconds later then repeats, also when pulling at wide open throttle in second it pulls hard until around 5000rpm where the power completely drops off and its like its hit a brick wall or something, its kind of similar to how it feels when it loses power and starts bucking but more extreme.

The only other indication of a problem is that the catalytic converter heat light comes on sometimes once its warmed up. I think the problem might be that the cat is bad but I could really use some help diagnosing the problem, thanks .

Dave

 

certainly sounds like a clogged exhaust... Try running it without the catalytic converters?

 

Hey, I solved one problem, the power no longer cuts out at part throttle anymore, turns out one of the hoses from the air box was cut, so I replaced it.

The problem is it still bucks in second between 4500rpm and about 5500rpm, after that it pulls hard to red line. I've checked my TPS and one of the numbers is slightly out of spec when its warmed up ( the green wire closed voltage is 0.66v instead of 0.75v - 1.25v which is the range its supposed to be). Do you guys think this could be whats causing the bucking?

One other thing ive noticed is that a couple of days ago, on a steep incline, the idle droped to around 300 and took a while to rev when I hit the gas, maybe the fuel pump is the problem? I did the fuel filter a couple of months ago so i doubt that is the problem.

Thanks for any advice you guys can give.

 

This sounds like it might be excess boost and the corresponding fuel cut.

Do you have a boost gauge installed?

David

 

Hey just took it for a drive to check the boost, it was boosting 10-8-10 but as soon as it returned to 10 thats when the bucking starts.

 

Try putting a new sock(fuel strainer) on the fuel pump in the gas tank, also check your air filter and check your Cat,it may be plugged up................................................ ..........

 

Is it only in second gear that it bucks at 5,000 rpm? Use the service manual and try testing your Boost (Map) Sensor. You might find if your voltages are off by quite a bit, the ECU is cutting the fuel early to prevent over boosting.

 

Yeah it only happens in second gear, will do.