Low power and awful idle

[Newtosn95]

Just bought this car so I know little to nothing about it. Everything is stock except for catless xpipe but still has mufflers and resinator. First thing I did was new iridium spark plugs gapped to .054 I believe. But car will jump up and down at idle between 500-1000 and then just die. But has no issues idling when in neutral and in motion. Also had decent lack of power. Any thoughts on what it could be?

 

[ttocs]

is the check engine light on? If so youtube shows how you can check codes with a paperclip. It is a good starting point

 

[joemomma]

Ditch the iridium spark plugs first. Go with standard copper, that's the best thing for these cars. Have you done a base idle reset?

 

[Mustang5L5]

Ditch the iridium spark plugs first. Go with standard copper, that's the best thing for these cars. Have you done a base idle reset?

I concur. Every 5.0 i've ever wrenched on has been tempermental about platnium or iridium plugs. They all seem to like copper

 

[96blak54]

When in doubt, copper out!

Use copper to at least rule out spark issues, then go from there

Also the stock distributor has a service life and then give weird issues

 

[RAU03MACH]

distributor cap points and button should be checked as well
also check timing

 

[ttocs]

I have never tried the fancy dancy expensive plugs because everyone I know and trust with motor advice has said to stick to the copper with the old pushrods.

Now I will say that do not just assume the parts guy knew what he was talking about, grabbed the right box(and that it was packed correctly) and everything is kosher. As you pull them out of the car put them next to the new ones real fast just to make sure they are the same length, right amount of threads, ect. I had the parts guy screw me and had me chasing my tail for some time because he grabbed the plugs for the stock heads after I told him I had aftermarket trickflow heads that needed a different plug.

 

[Newtosn95]

Ditch the iridium spark plugs first. Go with standard copper, that's the best thing for these cars. Have you done a base idle reset?

How do I do the base idle reset?

 

[Newtosn95]

is the check engine light on? If so youtube shows how you can check codes with a paperclip. It is a good starting point

How would I go about doing that??

 

[ttocs]

you do a search on youtube and watch the video that shows you how to do it. Just do a search for 94 mustang check engine codes

 

[joemomma]

Or you can get a OBD-I code reader at VatoZone for $30. Money well-spent.

The base idle reset procedure can be found online, just do a search for it. It may even be floating around on the forum somewhere.

 

[RAU03MACH]

do a quick check on you cold air intake sensor it will be the small plug in in the air inlet tube
make sure no oil dirt or residue is coated on it that will send out false readings

 

[Newtosn95]

Or you can get a OBD-I code reader at VatoZone for $30. Money well-spent.

The base idle reset procedure can be found online, just do a search for it. It may even be floating around on the forum somewhere.

I have tried three different code readers and none of them can get into the system

 

[ttocs]

checked any fuses?

 

[Newtosn95]

No but I certainly will tmmr thank you!

 

[ttocs]

don't forget under the hood as well as under the dash. it only takes a couple of minutes to pull and either visually inspect or better yet use an ohmmeter to check them

 

[joemomma]

Innova 3145 is your friend. The plug is under the hood on the passenger strut tower. The OBD-II plug under the dash isn't active.

 

[Newtosn95]

Innova 3145 is your friend. The plug is under the hood on the passenger strut tower. The OBD-II plug under the dash isn't active.

Wait what??

 

[ttocs]

yes there is an obd2 plug in the v8s but it does not work. The v6s had it and they knew the change was coming so they started the wiring expecting to change over to obd2 but never did till the 4.6

 

[joemomma]

94-95 V8 are still OBD-I, V8 didn't go OBD-II until the 4.6 debuted in '96. The V6 had it earlier as mentioned by ttocs.