My car will idle rough when it is in the driveway. If I step on the gas a little the car boggs down and dies. If you give it just enough throttle to bog it down but not stall it and hold it there, the car will rev up after a period of time. It is a s5 tII w/ j-spec engine and ecu. Here are the details. silinoids are good
Just replaced most of the vacumme hoses
AFM tested and works
TPS set within specifications in FSM
battery is charging fine, (13+volts)
I set the timing with the marks on the main pully, they are exactly where they should be, even opened up the , shoot forgot what the thing is, you stab it, I want to say electronic spark advance... anyways I made sure it didnt move any when I put it in.

Boost silanoid makes a weird noise.
OMP isnt pumping oil for some reason, re-wired directly to the ECU.

Anyone got any ideas? It was reving up very high before this problem. I took apart the TB and that fixed that. Another question... Which way are the throttle plates supposed to be like?
A:
/
\ / IC
or
B:
\
\ / IC

 

Hmmm.... does is still idle rough when its in the street?

 

Anyway laughs aside:

My car has a similar problem, except it will only do it when cold. I have to hold my foot on the gas pedal to keep the engine from dying, but if i give it too much gas it will die (much like your problem). I have to give it just enough throttle to keep it from stalling, but also not too much to keep it from stalling.... i will have to do this for about a minute while the engine warms up, then it will be able to idle on its own.

I believe it has something to do with the ecu adjusted timing, and my coil packs. You should put the car on a timing light and see if your leading plugs are firing on both the initial spark, and the waste spark reliably

 

Ill try it with a timing light on the car. It will idle fine, nice smooth quite, usually... but the problem with giving it throttle will happen even when the engine is nice and warm. Anyone else have any suggestionS?

 

bump, can anyone answer the question on the way the throttle plates on the TB sit? mabey a picture?

 

My first thought was a prob with your ignition system, but if the timing light works, then the CAS, coils and wires work.....
The only other things I can think of (in no particular order) would be:

1. fouled plugs
2. clogged exhaust
3. lack of fuel (check filter 1st, fuel pump 2nd, then lines and fuel rail, etc.)

These may seem basic, but in my experience, the basic stuff is usually the stuff I overlook.

Good luck

 

Checked the CAS, the connectors are at 170ohms, or Megaohms, nevertheless they are w/in spec. The coils are only getting 6V or .5V when the ignition is turned to the on position, could this be the problem, the car is basically flooding out? Where would the voltage loss occur?

 

I think the coils should be seeing a full 12V+ with the car on.

What's the ground connection on them look like?

-=Russ=-

 

Well the wires that connect to the coil are only getting the 6v, the connectors look good I am wondering if they dont tie into the ignition somewhere and not make a good connection.

 

i have the same problem with my two na fc
i can mess all the adjustable screw on the throttle to
make the rpm almost no going down.
but then my tps volt is all mess up!!!!
if no one know how 2 fix this.
i'll just install a wide band o2 that i've for other project
to see if it way to rich/learn.
somewhat i like to think that the a/f is not right,
becasue the air rush in when the throttle is start to open.
and that's only when it all happen.
if not a/f then i'll move on to ignition

 

Xfeast- exactly WHICH wire (color) are you reading to ground when you're getting the 6v?

 

im reasing off the black and yellow wire on the connector.

 

i was reading off the small connector that the FSM tells you to check the voltage from...

 

bump, any suggestions?

 

bump for me again

 

I would have guessed Vacuum leak.. OR an AFM problem.. Check all that, and check your AFM plug

 

Checked them all, vacumme hoses have all been replaced and the AFM is good so are the other 3 I tried. The connector to the AFM is in good shape also.

 

Resurrecting this thread because I'm having exactly the same problem, and I was wondering if a solution was ever reached for this problem.

Assuming it was a fuel problem, I've replaced my fuel filter, regulator, and fuel pump, all with no change. My car is an S4 NA.

The problem first occured when I was driving down the highway. The engine eventually stalled and wouldn't start back up, so I assumed my fuel gauge was busted and I was out of gas. I can now rev the car up to about 6k in neutral if I depress the gas pedal very slowly.

Any suggestions?

 

A couple more things:

It idles at about 1000-1100 rpm, even when cold. Before this it would always go to 2k rpm when cold. I tried disconnecting the TPS, and it made no difference. I played with the TPS a little while the car was running, and it did change the way it ran.

Also, I unplugged the vacuum line going to the MAP sensor, and the idle rpm increased. Covering the hole/nipple on the intake manifold made the rpm drop back down. So I guess the problem is not a vacuum leak.

I'm going to try testing the AFM if I can find my copy of the FSM or an operational website that has it.

 

The car should at 750 when warm. I could check your TPS and timing. also, get your plugs changed and an oil change, these can also affect the idle.

 

I recently set the TPS. I'll check to make sure it hasn't wandered. Timing was good just before this problem started, but since it idles just over 1000 rpm, I don't think I can check it properly now. Plugs are new and I changed the oil within the last 500 miles. Also, I just swapped the coils and igniters (leading and trailing) for ones from the junkyard - no change there.

 

Vaccuum leek?

 

I think if it were a vacuum leak that the rpm would have dropped when I pulled off a vacuum hose. Instead rpm increased, indicating that it was probably running a bit rich.

Thanks though. Any other thoughts?

 

You can't rule out a vac leak by pulling another vac hose....

Anything done to the car right before this happened?

Runs the same whether in neutral or not?

Any codes?

 

The last thing I did before this happened, besides take it on a nice drive through the mountains, was replace a couple resistors in the ECU. They were related to the catalyst air supply.

Haven't tried putting it in gear or pulling codes. It was in gear (on the highway), however when it first started having this problem.

I just checked the AFM using the FSM proceedure. It checked out okay, but I have one concern. When I checked the resistance between E2 and Vs, it was within specs (50-500 ohms) fully open and fully closed (~460 and 80 ohms respectively), but when it was halfway open, it went up to over 1000 ohms. Is this normal? Looking at the diagram, E1 and Fc tell whether the flapper is fully open, and E2 to Vs should give the position of the flapper. I would have guessed it should go smoothly from one resistance to another as the flapper is pushed open, not go up and then down...