hello i have a strange problem with my 1990 3.1 v6 manual trans
when i press the clutch to change gear the rpm stay at the engine speed I'm driving for 1 second (say 1600rpm) then go up to 2000 and after a few seconds down to 800rpm like it should be
when the car standing still there are no idle issues
it is really annoying to drive i changed lots of sensors and parts but it doesn't help anything the timing is also correct

i hope that somebody can help me thanks

 

I had a problem like this on my 92 3.1. The rpm would stick at 2500rpm or so until I stopped completely and didn't move for a few seconds. Then it would settle back to idle and then act normally the rest of the drive.

Never figured it out.

 

I found out that 2 spark plugs are fouled on my car
i read on manual trans cars to clear the rich condition that appears when the throttle plate is suddenly closed (when you change gear) the air pump shoots air directly into the cat and the rpm should stay shortly at 1100 then go down to 800
but it should sink to 1100 rpm fast , mine go up to 2000 . makes me mad
maybe it will work when i fix the 2 fuel injectors