1998 Audi A4 Quattro Base 4 Cyl 1.80L
Why is my vehicle in limp mode?
I have a 1998 audi a4 1.8t 5 speed manual (the vehicle selector on this website didnt show it as an option) and it currently wont rev over 2500rpms and it accelerates VERY SLOWLY. Top speed is 55mph in 5th gear. I ran a compression test and found that cylinder 4 is at 125psi while the rest are at 145psi. All of my cylinders are reading misfire codes. I have to drive with the gas pedal to the floor and occasionally enough boost will build to push it over 2500rpms, but it revs to 7000 shortly after and takes off. I also go through about half a tank of gas in 20 miles. Whenever I downshift I blow out black smoke (presumably gas). Another issue I noted (that could be unrelated) is my coolant temp gauge doesnt work.
The reason for the engine in limp mode is due to the misfire codes and the slight low compression. First question - what are the specific codes?