Gutless over 4500rpm

[blk_srt]

So I was driving around tonight and usually I shift at 3000-4000 rpm to consirve gas and becasue I dont need to go any higher lol but tonight I tried to take it up to 5500+ but once I hit 4000-4500 it just seemed so gutless. I fixed the fuel cut problem(just lowered the boost to 11-12psi now its fine) but now it wont rev any higher. My first thoughts are either a boost leak, running lean, or bad compression. Any one of those sound right? I'm going to do a compression test on tuesday or wednesday so I'll find that out and I'll probably make a boost leak tester sometime this week and test that. Any idea as to what it might be? I mean its like as soon as I get between 4k and 4500 its not that it doesnt rev its just there isnt any power there. It pulls great untill then but its like going from a TSi to a festiva lol

[UncaringMrBC]

my car has the same problem....91 tsi....i changed the fuel filter and it was fixed for a month or so then it started again....if you find the solution please post it back...

[ez1286]

What kind of fuel pump do you have? If it's stock it could be going bad. Could also be some kind of ignition, how old are your plug/wires? You can check the resistance in the wires, it should be less the 8k ohms.

[blk_srt]

Originally Posted by ez1286

What kind of fuel pump do you have? If it's stock it could be going bad. Could also be some kind of ignition, how old are your plug/wires? You can check the resistance in the wires, it should be less the 8k ohms.

Stock pump, new ngk bpr7es plugs and new oe wires.

[ez1286]

Do you have a voltmeter? If so just check the resistance to eliminate the easiest possibility.

[blk_srt]

I think it has to deal with the fuel system wether it be filter or pump because I've been getting really bad milage and I've been getting more and more fuel cut like its getting worse

[ez1286]

Then I'd say go for fuel, filter is easy and cheap so try that. then try fp, then injectors

[crunchymilk55]

for the bad fuel mileage, replace the 02 sensor. A faulty 02 sensor will keep your car in "safe mode" and you'll get around 10mpg, maybe less.

Are you saying your car won't rev at all past 5.5k? Does it do this only in gear or in neutral?

[blk_srt]

For the milage I'm getting an average of 16 highway and thats not getting on it at all. right now my gauge reads half with 55 miles on the trip. I think the cold weather has alot to do with the problem because it seems to get worse when the weather gets colder. It will rev bast 5500 but it feels like there is no power like the power band drops off at 5k. Today when I was driving to school at 11 on the highway I went to set my cruise at 75 and I let off the gas and the speed fell a little and then the cruise started to speed up I hit full boost which is only 11psi and the car started jerking and I'm thinking to myself that my tcase was going out again because thats kind of what it felt like minus the noise. So I made it about 8 miles to a rest stop and I pulled over and shut the car off and looked under the hood and couldnt see anything wrong so I started it up and it was fine. did the same thing after school. the weird thing is when it was having this probelm my turbo was hitting full boost at like 10% throttle which usually doesnt happen at least for me. I'm going to replace the fuel filter and do a compression test and a boost leak test and see if that comes up with anything.

[Thor06]

Yeah dude, you should not be getting half of the summer MPG in the winter simply because its winter. I've heard that milage goes down in the winter, but I have never seen it myself so I would be suprised to even see a 2 or 3 MPG decrease. I would go with what I think crunchymilk said, bad o2. If your milage sucks that much ass, you're getting plenty of fuel, I dont think its a fuel delivery problem.

[blk_srt]

Well according to the snap on modis scan tool at school my motor is running lean and my ecu is richening it up. The o2 sensor is fine. I mean its not like im getting 10mgp or less, summer and winter have staied the same at about 16, the best I ever got was during the winter and that was 20 and that was about well going on 3 weeks ago its hard to diagnosis because alot of the problems are intermintent. I'll just have to take it one step at a time and eleminate things as I go

[crunchymilk55]

bingo, there's your problem. You said your snap-on thing said you were running lean, right? well, let me guess, that thing probably reads off the 02 sensor wire, right? When an 02 sensor is dead, it sends out a very lean signal to the ECU, so the ECU sends a shitload of fuel. Again, safe mode. This would also explain why you're bucking at high rpm, you're bogging the engine with so much fuel. Replace the 02 sensor.

[blk_srt]

I got to thinking about that today and thats exactly right. I'm going down to Napa right now to get a price

[blk_srt]

Just got back from napa, $51.77 tax included for an oem O2 sensor. I'll be picking one up as soon as I get the cash

[blk_srt]

I got my logger today and hooked it up and according to that my O2 reading is jumping all over the place. I have it looking at the upstream sensor and its fluxating so fast its just a blur on the logger almost. Does that have anything to do with my problem?