Why is it when driving the RPM gauge drops or jumps up?
When I'm accelerating and get to required speed my RPM gauge either drops and steadies or jumps up then steadies back. Also if i push her too much to go faster too quickly it starts acting like the transmission is slipping. I've figured out that if i stop (in a safe place, of course) and cut the engine and wait a few minutes and restart the engine the transmission is fine again. I was told i needed new intake gaskets, i did that and it's still happening? could it be a sensor?
Is it just your tachometer or can you feel the vehicle surging? Any errors codes or is your check engine light on?
I agree with oldturkey - the first step is to check the computer memory for trouble codes. From your description, you might have a crankshaft position sensor or camshaft position sensor that is starting to fail.
My service engine soon light is on and the code it's throwing is multiple misfire, but that is a whole different issue. I know what that is from. It wasn't throwing any codes when this started happening but i was told i needed my intake gaskets replaced. But after having that done it didn't fix the problem. It is just the tachometer jumping unless i come to a stop then the car sometime, not always tries to lunge forward.
Okay, thank you Bill for your insight. I will have my mechanic check the sensors you mentioned yesterday. As for the multiple misfire code, i need to replace 2 of my coil packs and get new plugs and wires before i'll know the extent of the over-haul i'll need to do. But i do appreciate all your help and wisdom.
Need help i have an 2005 toyota sienna and when i start it it goes straight to the number 1 it use to idle in 0 area and now when i drive it and com to the stop light and to move off it jumpor i have to rev it to move can anyone help me please i have change transmission fluid and filter this pass week already.