Misfire?

[SolidState]

Hey guys...I changed my plugs and wires a couple weekends ago...

Now I have what seems to be a slight misfire.

My car idles at about 600rpm, which I think is low. It is also running really lean, and really rich. Bad o2s, leaking exhaust at the EGR, bad intake gaskets, vacuum leak due to the open EGR...

Could any of these cause a slight miss?

 

[Mr Anonymous]

Yes. Vacuum leaks allows unmetered air to enter the combustion chamber, causing a lean mixture which often results in detonation/pre-ignition.

 

[SolidState]

thanks, chris....I was thinking something along these lines...

will it also rob power?

 

[BeatDaSHO]

well......i'm thinking that u put the wires on wrong. search for plug wire sequence in the search. i think u put them on wrong.

Greg

 

[projectSHO89]

Mis-wired plugs won't cause a "slight" miss, they will cause a "MAJOR" miss. BTDT.

Steve

 

[Electric Frost]

Teg I would be willing to bet at least a few dollars that when you put everything bck together something was a little loose and came apart. Sounds like a vacuum issue really to me. You said it ran great right after you changed the wires, etc, right??? So it's probably something simple & stupid!

 

[SolidState]

the order is right...

I know I have vacuum leaks, I am just praying that the rear banks seals aren't leaking

the front is still dry, and the plugs were properly gapped...

 

[sdpatt]

If you know that you have vacuum leaks, why don't you fix them? If your engine is idling at 600 rpm, it doesn't sound like you have a vacuum leak anyway. Vacuum leaks don't usually cause a misfire.

With a vacuum leak, the idle would be very high from the extra air. You should try to reset the idle speed to see if the EEC and IAC can control the idle speed.

That list of problems in your first post - are those guesses or did you check the codes? If you checked the codes, will you please let us see tham? If you are not getting the CHECK ENGINE light, the primary cause of a misfire is either the plugs or wires. Just what brand of plugs and wires did you install?

 

[SolidState]

genuine motorcraft in both cases.

I'll get back to you on the codes. I know I am getting a 176 and 177...

there has been a couple times where I have goosed the throttle, and it stayed at about 2k rpm....would not come down what-so-ever

<small>[ April 09, 2003, 10:29 AM: Message edited by: SolidState ]</small>

 

[SuperG]

I had a similar problem (high idle after acceleration), which was solved by reseting the idle speed...

 

[SolidState]

Hey guys.

I took off my EGR tube/valve tonight and capped the intake...sans EGR to Intake gasket. So now it has a big leak there, and it is having trouble idling.

I unplugged the MAF and it smooth things out, except the bogging...

 

[Mr Anonymous]

SolidState:
Hey guys.

I took off my EGR tube/valve tonight and capped the intake...sans EGR to Intake gasket. So now it has a big leak there, and it is having trouble idling.

I unplugged the MAF and it smooth things out, except the bogging...

Wouldn't it be easier just to fix the car properly instead of going out of your way to make a bad situation worse???

 

[SolidState]

Actually, I have a new EGR tube coming...along with intake gaskets, EGR gaskets, TPS, and soon after o2s. Hunting down SHO parts in canada can be even harder than the US...

I'm not leaving the MAF unplugged. I just unplugged it to see if it was my problem.

 

[EO's SHO]

I have a 93 SHO ATX with 132K miles. I just wanted to know if driving on the car while it misfires would cause the O2 sensor to go bad. I'm in the process of getting new wires and plugs put in because my wire #3 went bad. But now I am getting an code 176 & 177, Saying lean & rich air. I'm new to the SHO's so I'm still trying to learn any help is much appreciated.

 

[projectSHO89]

Emmanuel,

Welcome to the Forum!

The 176 and 177 codes directly contradict each other and usually indicate that the sensor itself is bad. That sensor is for the front back, the #3 cylinder is for the rear bank so there is no likely connection between the #3 and the O2 faults for the front sensor.

Make sure you check for oil in the plug wells as that would indicate some additional work will be needed. Hate to see new plugs/wires go swimming in oil...

Steve in Florissant