So i was driving my car home from work and the car drove perfectly. Later on that night i went out and when i hit up to 4k+ rpm's the car would just start bogging and i would have no power at all.

About a half hour later I drove my car again and it was back to normal. Whats wrong here? Could it be fuel air ratio?

 

Hello

 

Something to do with the 3800 rpms hesitation, is your fuel filter clogged?

 

secondary injector come online at 3800
meter your secondary injectors at ecu
they should be at 12v then drop to like 7
it could be your injectors or ecu
if it goes to 12 then 7 then back to 12
its probably ecu
thats what happend to me

 

It very well could be. I havent changed it ever but could of been replaced before i bought the car, and ive had it for about 5 months now.

Oh, and another problem i have is my oil pressure gauge doesnt work anymore, im assuming its the gauge itself or some type of censor but dont know where the censor is located.

 

Is your car turbo??? if so you might have a big vac leak. If not then you should redo all your factory grounds, if that doesnt work seafoam it.

 

Car is a 1986 s4 n/a.

And you know what im glad you said that about factory grounds because when i swapped out my factory battery cables for new ones i remember half assing the ground to the left side of the body just till i have a connection piece. So at the moment all the pieces of wire are grouped up and clamped down with a screw to the body. Haha im an idiot. Ill get a connection piece today and see if that helps.

 

Check/clean your secondary injector connections, it always fixed the 3800 hesitation for me and a few others.

 

The stock oil pressure sender is on the rear housing right below the oil filter, I have had the wire get pulled off by my shirt sleeve when I was changing spark plugs.