solidsnake66

My girlfriends car has been getting terrible gas milage and is idling really rough. It also seems like the throttle is sticking especially when the engine is cold.

To start off I recently had to replace the valve cover gasket because she was leaking oil all over. The oil leak has stopped. This improved her performance and the idle a little but it's still terrible.

Up until now she hasn't taken very good care of the car.

I decided to seafoam the car for her. I dumped a can in the gas tank and I'm waiting on her next oil change for the crank case. I took off her intake and and sprayed a bit of deep creep in and started the car without putting the intake back on because I wanted to see if the tb was still sticking. It stalled out within a few seconds. I tried starting the car again and it ran a few seconds longer and stalled a second time right after throwing a CEL for the MAS which I expected since the intake was off.

At this point I reinstalled the intake and reset the ecu by pulling the battery. I started the car and again it stalled. One more start and it was idling really rough. We took it for a drive and it stalled at every stop until I got it on the highway and drove a few miles. Now its finally back to where it was at the beginning.

I usually leave the intake off on my car until I know the tb is good and clean so I didn't expect this behavior. Can anyone give me some insight on this or any suggestions on getting the tb to stop sticking and get her idling normally? I've been searching and so far haven't found much useful info. This may be because I only started working on our cars more recently and don't exactly know what to look for online to fix her issue.

Thanks in advance!

blaze_125

iTrader: (8)

For some reason the Lancer doesn't like running without a filter on. Even if the mas is connected, it just doesn't like being wide open without a filter.

The eratic idle and stalls after you reset the ECU, well, that's also "normal". It usually takes quite a few miles before things get back to normal as you found out.

As for you actual question... You first have to find out why the TB is sticking.
It could be the actual throttle plate that sticks, it could be the cable, or it could even be the pedal.

You cleaned the TB, so I guess you could rule out the plate sticking and move on to the cable and pedal. See if there is some sort of dirt build up where the throttle cable is exposed right before the tb. Maybe a gunk buildup keeps the cable from operating normally when the car is cold. When the engine is cold, the gunk is harder. The gunk will soften as the engine warms up. That would explain why it's more noticeable when the car is cold.

Another possibility would be... the cable is set too tight. On the intake manifold, there is a brass plate that holds the throttle cable. If it's set improperly it may keep the throttle plate partially open even when you're not stepping on the gas. If that's the case, it will give you the impression that the throttle is sticking and it will idle like total cr@p. As the engine gets warmer, so does the cable giving it more flexibility and maybe allowing it to close tighter as the engine warms up. I'm just thinking out loud here. Don't quote me or anything, but at least have a look at that brass plate and make sure it's not keeping the throttle cable to tight.

For the Lancer, this is the place to be. There is simply no other place on the web with as much info as this message board for her car.

solidsnake66

Thanks for all the great info blaze_125! This weekend I took a look and the cable and everything seemed good. I ended up taking the whole TB apart and giving it a really good cleaning all around with deep creep and a toothbrush. Once I did this the TB stopped sticking!

The car is running much much smoother now. But it's still idling a little more rough than it should, I'd like to run a bit of seafoam through her vac lines. Any suggestion on where would be the best vac line to do this? I know where mine all are on my car, but I'm not so familiar with her car.

In a few weeks I'll also be flushing her transmission, since she has 125k miles on it I think it's about time.

She doesn't take care of her car at all so now I'm trying to get it running better for her. Thanks again!

dacib

iTrader: (1)

You can use the vac line from the brake booster. Try also to clean the MAF and EGR valve.

blaze_125

iTrader: (8)

If the tb isn't sticking anymore and there is still a idle issue... you may want to play a bit with the idle screw. My guess is that the car idles too low and it periodically "revs up" to stay alive.

I posted a screenshot a while ago of the idle screw location. I'll see if I can find it.

edit:
https://www.evolutionm.net/forums/9314280-post13.html

solidsnake66

So would I adjust that while the car is running or should I adjust a little by little with the car off and then start it to see where it's at?

BTW I know it's been idling at right about 500rpm's. Is that normal or too low?

blaze_125

iTrader: (8)

You'd be adjusting it while the car is running.
It looks like you worked on cars before, so I don't have to tell you not to wear loose clothing while you work on a running car... an XL loose shirt can quickly and easily get caught in a running belt

500 is a bit low. 700 is what you're aiming for.

Juan Martinez

iTrader: (1)

My old one did this too. It had the recall problems that the 03 had with relay/o2 sensor/ exhaust problems. It idled at like 1500 most of the time.

blaze_125

iTrader: (8)

I beleive you are talking about a seperate problem that gave a P0421 cel. If I'm thinking of the right problem, you prolly had to bring the car in for an ecu reflash that affected the cold start fuel map or something.

solidsnake66

I've been learning as I go. My dad taught me the basics including no loose clothing LOL. Been changing brakes and oil and normal maintenance for years, but more recently have been getting into more involved jobs.

It started as I wanted to save money since the mechanics always cause a butt-hurt with the bills. Now I'm having fun working on our cars haha.

I'll adjust it when I get home later and let you know how it goes. Thanks again for all the info!

prezdead

My '04 OZ was idling rough as well... my first thought was to replace the spark plugs. It did the trick for me.

It might not fix the idle in your gfs case but its a cheap place to look.

.44 is the gap I believe. There's a good write up (links to pics are old I think) in the how-to section.

EDIT: Mine idles steadily around 800 rpm.

solidsnake66

I just changed the spark plugs about 2 months ago and made sure they were gapped propperly.

I adjusted it so it's close to 700rpms according to the guage. Now I can feel it reving up and down a little. I got a bluetooth ODBII adapter I ordered in the mail today so I decided to test it out. The guage doesn't show this but the software shows the rpms bouncing from 650 to 750 and back again.

Can anyone explain to me or post a pic of where/which vac line the brake booster is? I still want to run seafoam through there.

blaze_125

iTrader: (8)

It's a big thread, but I know the info is in there
https://www.evolutionm.net/forums/la...-sea-foam.html