Engine RPMs climb slowly after running for 10 minutes. Help!
 

Hi folks, I'm experiencing a strange problem that I couldn't find anything about after doing some searches.

I have a stock 1991 NA car which I recently took apart to replace all the vacuum lines on. As far as i can tell I put everything back together properly but I have developed what seems to be an engine management issue. When I first start the car everything is perfect but consistently after about 10 minutes of running the engine starts accelerating very slowly. There is no sputtering, the car still idles fine and can hold its rpms, it just won't rev up quickly even when in neutral. After I stop the engine and start it again...the problem is gone and the engine revs up perfectly again. Any ideas what has happened and what I can do to fix it?

got video?

Check for codes.

Ok I found out from doing some more research that my car is going into "limp mode". I forgot to mention I also replaced the oil metering pump lines and put a new gasket in between the pump and the engine. Maybe something got shorted out and the omp is setting off limp mode....although the oil lines seem full of oil like the pump is working. Guess my next step is to take the car in and have a shop check for the error code...

Resolution
 

After getting error code 27 I found out in the shop manual that there was indeed something wrong with the oil metering pump. So I took out the air cleaner and radiator fan/shroud again to check it out. Wires looked ok both the harness and going to the position transmitter. Then I noticed in a little nook on the radiator that there were three little spacers or shims that looked like they were the same shape as the position transmitter. Doh! I had dropped them without realizing it when I first took the metering pump off. Luckily they hadn't fallen out when I was driving around! So I put the spacers back between the pump and the position transmitter and voila! No more limp mode :)

Nice work!