hi, when i start the engine, the (rpm?) gauge moves up all the way to 2 and when i put it into reverse/drive, the car kinda jumps/bumps. a mechanic says i'm not supposed to change gears right away after i start my car, but i don't do that, i let my car warm up a bit before i change gears and that's what it does. what should i do? thanks

ps- i have a 95 ls

 

ok my sisters mustang dose the same thing when she puts into reverse and drive. i had my dad check it out when i noticed it and he said not to worry about it that it was normal in most auto cars. I dont like it it feels odd to me lol but ya, thats my opinion.(dad is a machanic)

 

It's called a high idle. The engine will do that when it's cold. Nothing to worry about at all.

 

Yes, the engine should idle higher when cold. However it really shouldn't go any higher than about 1100 RPM. You most likely have a bad fast idle thermo valve.

Here's how you check the fast idle thermo valve. I've also included the process for how to adjust your idle setting if you need to replace the valve.

 

its normal. its from the high idle that your car does when the engine is cold.

when your car is warmed, shifting from park to drive will be around 750rpm. when its cold, you are doing it at a higher engine speed, probably meaning more movement (jerk) from the tranny / engine.

:dunno: :thinking:

 

well i thought about it more and i was wrong my sisters stang didnt do this it was more of a break problem then a tranny problem (the breaks are new though) sorry. was a while ago.

 

the car should idle higher when it is in cold start.

as far as the car banging around when you shift it into gear while cold, most hondas do that, and any other auto trans that has a full ball style valve body and thick fluid.. the fluid is thick when it cold, and even though you have trans fluid pressure, the fluid sort of moves through the valve body in globs for a few minutes.. it's almost like oil in a pan, how it's all nasty, then when you warm it up, BAM, fully liquid..

hope this eases your mind. no prob. I do recommend switching to a full synthetic. redline D4 or the likes.
synthetic fluid has more ov a tendency to flow well while it's cold regardless of viscosity.

 

Yeah it should idle higher, up to about 1100 rpm. Spec idle with no adjustment is 750 +/- 50 rpm and the idle control system has a range of adjustment of about 300 rpm. The original poster says the fast idle is all the way up at 2000 rpm, which is indeed too high and definitely indicative of a problem with the fast idle thermo valve.

 

yeah, my teg does this too. only when its cold, it revs all the way up to 2k+ rpms, its jumpy for awhile after that, until it warms up.

 

I repeat: this is not normal behavior for the car.

Your motor has a system that is designed to raise the idle in cold weather by a total of about 300 rpm. If your idle goes all the way up to 2000 rpm when cold, then you most likely have a bad fast idle thermo valve. You should check the valve using the procedure I posted above.