rough idle...long

[silversteed]

I've been searching for the really bad idle problem both on the boards and under the hood.

It idles at around 900 RPM, well for the most part until it misses and drops 100 RPM and then over corrects to 1000 rpm, then back to 900.

I tried to do a KOEO to pull codes with then engine at operating temp and I *think* the codes were 57 and 67. I used a test light and wasn't really sure what I was reading with all the single blips of the light.

I've checked over all the vacuum lines that I know of and they seem fine. Tried some WD-40 on them also.

The TPS is set at .94 and it is smooth and goes up to 4.6 or .7.

Checked all the wiring and everything is connected, no loose wires. Moved them while it was running...no difference.

I just had a lot of the engine apart to replace the valve cover gasket. Cleaned everything I touched as everything was covered with oil.

I found a wire busted on the TFI so I replace the connector and redid the wiring for about 1.5 feet up as this wiring was in bad shape. I also found that the EGR tube wasn't screw into the TB so I'm sure this was leaking before. I think there may be a problem with it (previous owner...)

Car fires in a heart beat and runs pretty good when you have your foot in it, when you come to a light it drops RPMs a little too much but it recovers.

Not sure where to go from here, was considering doing a KOER test, but with my success of the KOEO test I don't think it will go well. I need to find a better way to read codes...maybe an LED.

Any suggestions would be much appreciated.

Thanks,

Jim

[BrianO]

mine has been doing this since I got it. it's not all the time, but while at a light or something the idle will drop from it's smooth 950rpm's down to almost nothing and then recover like you said. I have yet to pinpoint it, but I can tell you this.. I've replaced everything except the distributor itself at this point.

[silversteed]

Mine also shakes like it has about 3 cylinders.

[BrianO]

that's only because it is about to die and it kicks back on just like mine does.. I can only assume it's something like pulling the power plug real quick and putting it back in just as quick. I posted this question a long time ago and didn't get too far with it.

edit.. I never actually replaced the IAC valve although I planned to. I did remove and clean it very well, but it still does this every once in a while. I think it's electrical personally, but maybe it's the valve.

[Pat_in_L.A.]

It idles at around 900 RPM, well for the most part until it misses and drops 100 RPM and then over corrects to 1000 rpm, then back to 900.

That's after a couple minutes of warmup, right? Then it starts "hunting" up and down after the 02 sensor is finally heated up. That's WHAT IT IS SUPPOSED TO DO. If it doesn't do that, you have an old worn out used up Oxygen Sensor that will not pass smog inspections and cost you fuel economy. It's called "stoichiometric".

The RPM adjusts every time that the 02 sensor signals between rich and lean. The slower the transition, the older (*but not wiser*) the 02 sensor.

http://www.taftan.com/thermodynamics/COMBUST.HTM

Now look up "The First Law of Thermodynamics" and let's figure out where we will be getting future fuel.

[silversteed]

I drove it to work today and can better tell you how it is acting now. This is probably the furthest that I have driven it.

It misses when it is at idle, not really hunting but just RMMMMMMdadadaRMMMMM. sorry but if you could just hear me.

When I accelerate it sounds perfect but just holding steady speed you and feel it missing.

I roughly cleaned out the IAC when I had it all apart...I probably should soak it or buy a new on. To set the idle I need to take the electrical connector off but it hits the IC, is the because the IC is pushed up too far on the TB? Didn't notice it when I put it on.

[BrianO]

yeah this isn't a hunting issue at all. I have all new parts including O2 sensor... hunting is obvious, this is more like power is removed adn applied again right before the engine dies. most fords do the hunting thing while they are warming up.

just like silversteeds..mine starts great, runs great, but only at idle does it once in a while almost die, but then recovers

[silversteed]

I still have now idea where this miss is coming from. I have new plugs, wires, fuel filter, air filter, TPS set to .94, checked all the wires, checked for vacuum leaks, nothing! Everything seems fine.

It is still missing at idle, you can see it in the shifter and the engine going side to side. Driving I can't hold a steady speed as the miss is bad. So I down shift and when I accelerate it clears up. Then as soon as I let up it goes back to missing.

Any ideas?

Thanks,

Jim

[silversteed]

I do have one suspect hose that could be leaking. I tried the WD-40 test but it didn't show a leak.

I hope to make the Reunion, don't know yet as it is still to far out for me to make a decision at this time...but I'll bring the propane!

[silversteed]

I'm guessing...start the car and open up a bottle of propane and direct it at the different parts of the intake, look for an increase in idle?

[silversteed]

I only have two more hoses to replace and I have the new ones sitting at home, the 2 IC hoses. I have the Forced4 ones which will be a huge improvement over the old ones on there now.

If that isn't it then I may venture down the propane route.

[silversteed]

Put the TC IC on tonight and added a set of MC plus. The other plug were new, the plug wires were on tight, and the old plugs looked new. But damn! The car is running great.

Okay so now you have a new SVO owner on-board with nothing but MC ignition parts! Hard to believe, yeah really hard to believe!!!!

Thanks all for the help,

Jim