look into something wrong with the secondary injectors they come on at 3800 with load

 

you could also see if your ports and vdi are working... does it start hesitating to go or stalls out?

 

Definitely a lack of secondaries coming online.

 

Before doing anything else, I would first recommend cleaning the electrical connectors on the bank of 5 vacuum solenoids at left from of engine (in front of oil filler tube). Just disconnect the electrical connectors one at time and use a small piece of sandpaper to scrape the corrosion off the brass spade connectors. Don't try disconnecting the vacuum lines because you are likely to break the nipples off. I once had a similar experience on my 90 GXL. All of a sudden, it started running like crap. It turned-out to be from those solenoids having poor electrical connections due to corrosion. If this doesn't help, than move on to plan B.

 

Is the CEL (Check Engine Light) on? Even if it isn't, the 1st thing to do is to pull CEL codes from the ECU. Since it's an S5, the ECU will store all CEL codes it encountered since the last time the battery was connected. (i.e., disconnecting battery will erase codes stored). Good procedure for checking codes on an S5 can be found here:

89-91 CPU Trouble Codes

Do that first & report back. Does the car rev beyond 4K RPMs in neutral?

 

Push the pedal down more.

 

yea.. i had the same situation as you before. routed the vdi incorrectly. but do check ports as well.

 

OMP failure?

 

thank you i did this and still having the same problem ....gonna check injectors next

 

check injectors / aux port actuators