Sorry if this has already been asked. everything I found that came close to my issue the solution did not work.
I recently purchased a 1998 Audi A4. They where selling it because they could not figure out what was wrong with it. It will not accelerate over about 20 MPH unless rolling down hill. It also will not rev up passed 4000RPMs when in neutral. The car will not spool up at all. (either driving or in neutral) I read somewhere it may be a vacuum issue but I don't even know where to start. The MAFS was replaced, Plugs replaced, Fuel pump replaced. I took a look at the fuel lines in the tank and one of the return lines was kinked to the point where it stopped flow completely. I am not the one who replaced the pump but when I checked it the pump was not secured all the way down in the place for it. I un-kinked the lines as best I could and put them back in. That did not fix the issue. Maybe they re-kinked when I put them back in? I have no check engine light. I don't think it has anything to do with it but the ABS light is on and the brake light is blinking.
Side note: I have coolent leak coming from somewhere in the back of the engine block and the bottom hose to the coolent res missing. where does that line go?

 

Havent pulled the codes? Coolant leaking? Assuming it sounds terrible and bad vibration? Head gasket? Blown turbo? Just guessing, sounds like it needs alot more love before you worry about going over 20mph

 

There is no codes/ check engine light. With a blown turbo wouldn't it have a code? there is a bit of a squeaking sound when I try to accelerate over the 20. There is no vibration and no burning coolant/ white smoke so I didn't think it could be a blown head gasket

 

Meh , unplug the maf see if it gets better, maybe a clogged cat, make sure all the intake hoses are connected from airbox to turbo to manifold, assuming its an automatic? 4k rev limit in neutral/park? Would find the coolant leak kinda important, head gaskets can fail in multiple places, cyl to cyl, oil/coolant to cyl, oil to coolant, or leak out on either of the three so no white smoke doesnt mean wont be a head gasket, just sounds like power loss to me, and trying to guess simple things to check for major power loss beyond what youve already done, air gas spark compression and all thats involved with those... easy stuff first and dont throw money at guessing lol, coolant leak and no power says headgasket to me but could be something stupid + coolant leak, no misfires? , also not sure if you can but may throw some codes with a bit of driving, would take almost 100 miles before some codes were thrown for me after a reset, codes will give you something to focus on lol

 

Its actually a 5 speed. I found a leak on the rear coolant flange. Could that effect power to the motor? I replaced that but when I took it off there was no gasket on the flange or on the connection to the water pipe. I bolted it up and there is still fluid leaking from somewhere. I don't know if they are not tight enough or if they need a gasket. For the life of me I cannot tell if its leaking from there or not. It may have to do with one of the coolant reservoir hoses.My biggest question is I CANNOT figure out where the bottom hose goes to. WHERE DOES THIS GO?!

 

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