Ok so here's the deal (note I never go hard while the engine is warmed up all the way) so ive noticed my car will bog when the oil temp is at the temp it's supposed to be at if I go hard on it(while its not warmed up all the way the boost gauge reads a steady 8 psi after waiting 2 seconds with the gas all the way down. But once the oil temp is at its regular temp I have a BIG loss in power and gauge reads 4. Does anyone have any idea why this is? Doesn't make any sense to me at all. I'm REALLY hoping its just a vacuum leak? Any suggestions or help would be very appriciated. Another note changed plugs and gapped correctly, new fuel filter, fuel pump seems fine, and put some cleaner threw the fuel a few weeks ago when I filled up believe it was chevrons stuff.



Thanks!

 

If it's happening when the car is up to temperature, but not before, you have to consider that the car is operating on different parameters in each situation. In warm-up, it's in start mode, running on preprogrammed fueling and timing maps, and at temperature it's fueling and timing itself based on MAF, O2, and other sensor feedback. I'd suspect an issue with one of those as being possible. A vacuum leak is possible too - a split hose may open up with ambient heat from the engine.

Do you have any codes in the ECU? Even without a CEL you can have codes so have the ECU scanned.

Look at the boost gauge at cold idle (after the RPM drops to normal engine speed), warm idle, and off-throttle cruise. Proper vacuum should be -17 to -22 on the gauge. Higher than that indicates a vacuum leak.

Check this stuff out and post up your results and we can go from there.

 

Oh ok! Sweet alright will do thanks for the advice! I'll reply back later after I get home from work to let ya know

 

And no I have no codes and I have the cel checker so I'll be sure to check it

 

It seems to be running 19-21 but havnt started it completely cold yet

 

Ok, so cold it still stays between those numbers

 

Ok then as long as vacuum is in that range while cruising/idling warm, you don't have a vacuum leak. Could be one of the sensors I mentioned above, or coolant temp sensor as well (it's the root of a lot of screwy behavior). If you have your radio code, you could do a throttle body alignment (search feature will reveal how to do this), and see if throttle alignment helps. A Seafoam treatment could unclog a carbon clot somewhere, and I'd verify that your plug gap is correct at .032". Those are inexpensive and easy next steps.

 

I'll be sure to do the sea foam and stuff. Thanks for the help. And no oriley said .027" and coolant temp sensor read something about that mine as well replace it. Should I just get a stock one or is their a better one around the same price? And I need to read up on that throttle bottle alignment never heard of it


Thanks again very much been a lot of help

 

And there is also no codes on the car just checked

 

Don't listen to O'Reilly. Listen to Audi guys that know these cars lol. Your stock plug gap is .032". If you upgrade the ECU you're going to need to gap them down to .028". Without a chip, it's .032". Take that to the bank.

On the CTS, depending on what year your car is, it'll be black, blue or green. Get the one that corresponds to the color you currently have.

The throttle alignment typically is done after the battery is disconnected, but it doesn't hurt to do it so that you know it's set up right. Just know that you may put your radio into safe mode and need the code to unlock it (you can get it through Audi of America using your VIN number and the radio serial number though).