BigBas83

I used the search feature and found that most cars with a high idle problem were very high (like 2500 rpms).

At startup, more often than not my car idles a bit high, around 1100 rpms, instead of the usual 700-800 rpms. When I shift my car (A4) into drive, it makes a sound like it is trying to accelerate and pull away. I can also feel the force if I'm not pressing the brake firmly. Otherwise, while driving, I feel nothing wrong. When coming to a stop, the downshifts are not rough, but they are noticeable, and they almost feel like the car is trying to accelerate while stopping.

I don't know if any of this makes sense, but if it does, what do you suppose the problem is? Also, how would you recommend fixing it?

Thanks in advance

jmm98LS1

iTrader: (28)

Is this from a cold start? If so, that's normal. Your idle speed is based on engine coolant temperature, so the colder it is outside the higher your idle speed will be until the engine warms up. If this is from a warm start, how long does it do this? Every time your car starts, it operates in "open loop" mode (no input from o2 sensors) for a little bit until the o2 sensors heat up and kick it into closed loop. That may make your car idle a bit higher. It eventually settles down doesn't it?

BigBas83

I guess cold start is somewhat relative. it is about 70 degrees outside, so it isnt really cold, but the car is being started fresh (4-5 hours without use). The issue does seem to settle down one i put the car in drive; if i stop at a traffic light, it is down to normal RPMS.

What about the "surge" when i first put my car into drive? I don't think that can be good for the transmission in the long run. (Am i correct?) Also, should I be feeling the downshifts as much as i do? It feels almost related to the idle problem.

jmm98LS1

iTrader: (28)

Your idle speed will be faster when you first start your car after sitting that long, and it'll slowly go down as your coolant heats up. That's just how fuel injection works. The highest your car will idle is about 1100 rpms from a "cold" start. You aren't hurting anything by putting the car in drive when it's cold. Line pressure is very low in this situation and won't hurt a thing. Just don't beat on your car until it's up to operating temps.

BigBas83

so, i just started my car, and your explanation for the higher RPMs seems reasonable, but I'm still wary of the shift into park. The engine gives off a VRRRM sound, like its accelerating, then it sort of jerks into the gear. it feels almost as if someone would put the car in neutral, and rev the engine while thier foot was on the brake, then put the car into drive.

any thoughts? think it might be a sensor problem, or am i just paranoid?

jmm98LS1

iTrader: (28)

Paranoid.

Rebelord

iTrader: (2)

from a cold start most of that is normal. as for the tranny thing, yea, it does that when the tranny is cold to. you could check your fluid to see if you low any also. that wont hurt to check it

Doc

iTrader: (9)

I don't think that is normal at all. I think the difference btw your desired idle air in park vs. desired idle in gear is too great. Iv'e noticed that if the split btw them is too great on my car I got the same indications. I have found that if I keep desairpn + .1 over desairig the shifting into gear clunk goes away.