Ok. My stock S5 FC TII is having a problem with hesitation. Mainly between 3 and 5k RPMs but happens above and below that occasionally as well, on or off boost, not dependant on throttle position, revs cleanly in neutral, and idle is rock steady. Plugs are less than 5k miles old and pretty clean ( the trailing is a little fouled). All grounds are cleaned. Any thoughts? hesitation definitely feels like a spark cut not fuel or air. But if anybody knows any common problems please let me know.

 

Hmmm did you change you're spark plug wires as well?

 

No. Not yet. I found and fixed a vacuum leak, but i think the problem might have returned right as i was getting home. Also put new plugs in. If the problem is still there it is much less extreme. I'm going to change my plug wires next. Any other ideas?

 

You could have a fuel issue related to a clogged fuel sock, fuel filter, faulty fuel pump wiring, clogged injectors/poor injector clip connection. Also, faulty Water Thermosensor or TPS not properly set or Boost Sensor related or clogged exhaust and so on. Have you tried checking for error codes? And does the problem occur only while rpm's increase, steady rpm's, decreasing rpm's ???????????

 

Well try the plugs and try to post a video and let me know the results

 

Ah fixed it by unplugging a ground i had recently cleaned. Weird. All my vacuum lines needed to be replaced anyway. And it threw no error codes.

 

No never mind it's back. Still need to replace the plug wires. Probably going to need to reset the tps and maybe relocate that ground. Check for more vacuum leaks maybe? Idk this is getting very frustrating. It's not as bad as before but occasionally while cruising it still bucks and starts revving down.

 

Also it is not due to a lack of fuel. It's running way too rich when it does this. Just replaced my air filter at the last oil change. Boost is reading normal, and it still hasn't thrown any code yet. And it's a bit tough to film since I commute on the interstate and the occurrence is seemingly random. Does happen more at light throttle and cruising but not even always then.

 

Vac leak or S5 OMP throwing you into limp mode. Most likely the OMP. Had the same thing on my S5 TII. My OMP tested fine, but the connector pins in the harness next to the alt were oxidized and needed to be cleaned

 

Wouldn't limp mode throw a code?

 

It should, but it doesn't always

 

What was the location of the connector you cleaned? Have a picture??? I always thought this "bucking" problem was related to the TPS...

 

Its right next to the alternator