Idle issue...but different

[dwendele]

Ok, first off its at 98 420a. It's got a Greddy header and some kind of big chrome intake manifold. I don't know much about this car, I just got it a couple months ago to save gas.
So the problem. All of a sudden the other day it acted. Like the throttle stuck.... I'd put in the clutch and it would surge up to about 4k rpm. Sometimes it would creep back down, some times not. I parked where I was going and when I came back out and started it, it ran perfectly for over a week.
Now yesterday it did it again, so just to try it, I shut it off at a stop light.....wouldn't start back up. Finally I got it started by holding the pedal to the floor. It reved WAY up then settled down. Got home and it was idling high again. Tried the same starting technique and it did start, but ran REALLY rough. Coughing and sputtering. Also puffing black smoke out the exhaust. Also notice oil and smoke coming out of the oil breather.
Any clues?
Started it tonight and wasn't as bad, but was still running really rough.
HELP!!

 

[Infamous33]

Sounds like a throttle position sensor or ect. Did the check engine light come on?
You will have to test it while it is acting up. If it is shorting it self to power it will make the comp. think you have your foot on the gas. If it's the ect the comp. will increase fuel injector pulse width when it thinks the coolant temp. is really cold. Make sure it's full of coolant while you are there.
The oil and smoke out the breather seems like a different problem.

 

[HALO-GST]

was the smoke and oil coming out while the engine was hot or first thing while it was cold? also u might want to check the throttle cable and throttle body return spring make sure its not sticking, also take a look at ## idle air control solenoid/motor/valve sometimes if theyre dirty or if they go bad it could cause that problem as well...one more thing u may have some type of air leak in the intake/induction system sometimes those cause high revving as well......hope that helps

 

[dwendele]

The thing is, cel was on BEFORE this started...now its not. Found one vacuum line off. Only differencenow its it idles fine....until I hit the gas. It has a slow sputtery response, stays way high, then slowly goes back down.
I've been reading some more one here and am going to pull the tb and clean really well. Also, it has a monster of an aluminum radiator, and i think a colder than oem thermostat. It NEVER looks like it gets really warmed up. Going to try a hotter one. It's not cold here yet but it HAS been chilly in the mornings since this started.
Everyone seems to swear by seafoam too. BUT is that going to end up messing up my cat? I've had clogged cats on two different cars and that can get expensive.
Thanks guys!

Here's a pic. Is that one of the crappy EBay intakes I keep reading about?

 

[dwendele]

Ok, I cleaned the TB really well, seafoamed it, changed plugs and oil. It ran MUCH better, just had a bit of a miss. I also went to Autozone to have them check the code.....it didn't work. Got back home and pulled the negative batt cable to try to let the computer reset. When i connected again, it won't start at all know. I'm lost guys....HELP!

 

[coop795]

how long did you leave the cable off? did you do anything else at the same time?

 

[dwendele]

About 15 min....and no. Went out the day after and it fired right up, cel came back on and it ran better than ever for a day and a half. Now it's kinda back to where it was....but not as bad.
I know it's getting WAY too much fuel. At start up I have to treat it like its flooded...pedal on the floor. Gotta keep rpm up until it smoothes out, then it will run but still with a sputter. New MAP sensor comes in in the a.m. will give an update then. In the meantime, any more ideas?
OH! And when i got the plugs, it was 3 a.m., (I work nights) so I ended up with autolites, and i notice the threads are shorter.....so they don't go in as far? Should I get some NGK's?

 

[92AWDHX40]

I would there cheap enough.

 

[HALO-GST]

Did u try the NGK's? Is the CEL still on?

 

[dwendele]

Sorry for the delay. I did a couple more things from reading on here.
1) replaced map sensor......worked for a day
2) replaced thermostat.(was stuck open)....again, worked GREAT for a day.
The cel even went off by itself.
Now it it back to same old tricks. Let me describe again.

To start, I have to hold the gas to the floor. It will do this two or three times
Before it stays running. Can smell gas very strong.
Once it is running it spits and sputters, and just runs very rough.
Sometimes the idle will stick @ around 4k rpm.
When driving, if I push in the clutch, it will rev up to around 3k then back down to about
2k
Same thing a a stop light. Although, when the car rolls to a COMPLETE stop, it will idle down
To normal.
It is running extremely rich, can smell gas, mpg in the dump, and plugs are BLACK.
I'M almost to the point of taking it to a shop, but I really can't afford it.
HELP!
Oh, one last thing. When it is trying to smooth out at start you can hear it sucking air
into the tb .....like when you tap the gas.....that hard sucking sound.....but my foot isn't even
on the gas.
It seems to me it is getting WAY TOO MUCH gas, I just don't know why.