plugs/wires/iac quickies

[realitygt]

so my car has a misfire cold, it starts fine and after about 20 seconds when it idles down to about 1000, it starts misfiring...

I'm thinking it has something to do with the plugs or wires, the plugs are 5k miles old but I think I might've fouled one when I did the livernois pi intake swap, do you think i should do wires while I'm at it? they're the original wires, and seem to be working fine... no corrosion on either end...

also when going down the road, in neutral the idle will be at 1500 until I completely stop, then it will slowly go down to 700, is there anyway to make it drop all the way down? or is it just a ford thing? also If I just tap the throttle it will go up to 1500 rpms and come down extremely slow.. would it be because I have an advance auto parts iac instead of an oem one?

 

[CC'S95GT]

do the wires and plugs at the same time. surely they're not the original wires. the idle is supposed to hang a bit till you stop so you don't lose vacuum to the pwr brakes. but i think yours is a little excessive. mine hangs more than yours and i think it's the tps. also try cleaning the maf while your changing the plugs.

 

[GDawg]

My car just started running rough recently. I don't think it's the plugs or the wires due to the fact that it gets worse the warmer the engine. I'm thinking it has something to do with my EGR value. But, I'll also be checking for vacuum leaks, maybe bad gas or fuel filter. In your case, my guess would be vacuum leak. But it could be your wires or plugs. My car's not throwing any codes... I hate these sort of problems.

 

[Paul]

Reality - did you run codes yet? I'd do that first.

I'm having some similar issues with my 5.0 right now, and after $500 in sensors and having the car run worse now, I'm annoyed that I messed with it in the first place.

Paul.

 

[CC'S95GT]

gdawg- could be the o2's also. the car runs in open loop for the first couple minutes till the sensors warm up then it switches to closed loop and all the emissions kick in.
paul- after you swapped out all those sensors did you unplug the batt to reset the puter so it starts with all new inputs.

 

[realitygt]

Reality - did you run codes yet? I'd do that first.

I'm having some similar issues with my 5.0 right now, and after $500 in sensors and having the car run worse now, I'm annoyed that I messed with it in the first place.

Paul.

i dont have any codes besides the one for no cats.

it's not really a problem with the idle so much as annoying.

do the wires and plugs at the same time. surely they're not the original wires. the idle is supposed to hang a bit till you stop so you don't lose vacuum to the pwr brakes. but i think yours is a little excessive. mine hangs more than yours and i think it's the tps. also try cleaning the maf while your changing the plugs.

on the 5.0 do they have the hydroboost also?




the wires are the originals that came on the car, they say ford 1999


the misfires starts after about 20 seconds, and then only lasts for maybe 30 seconds, then runs perfectly fine, so idk

 

[CC'S95GT]

i have never heard of hydroboost before

 

[realitygt]

i have never heard of hydroboost before

it's where the brake booster operates off of power steering pressure instead of vacuum. i know my car has it.

so the idle thing, is not related to keeping pressure in brake booster

 

[GDTrumbo]

so my car has a misfire cold, it starts fine and after about 20 seconds when it idles down to about 1000, it starts misfiring...

I'm thinking it has something to do with the plugs or wires, the plugs are 5k miles old but I think I might've fouled one when I did the livernois pi intake swap, do you think i should do wires while I'm at it? they're the original wires, and seem to be working fine... no corrosion on either end...

also when going down the road, in neutral the idle will be at 1500 until I completely stop, then it will slowly go down to 700, is there anyway to make it drop all the way down? or is it just a ford thing? also If I just tap the throttle it will go up to 1500 rpms and come down extremely slow.. would it be because I have an advance auto parts iac instead of an oem one?

The dropping of rpm's slowly is there to help emissions. Engines w/ a manual trans tend to "puff" when the rpm's drop quickly (during shifts usually) and then rebound at a given idle setting. This can be altered with a modification to the IAC gasket. This requires creating a hand cut gasket with a precisley sized hole drilled into one side of the gasket.

I read the thread on this forum but I don't remember all the details.

GT

 

[GDawg]

gdawg- could be the o2's also. the car runs in open loop for the first couple minutes till the sensors warm up then it switches to closed loop and all the emissions kick in.
paul- after you swapped out all those sensors did you unplug the batt to reset the puter so it starts with all new inputs.

But my cars not throwing any codes... I'm even suspecting bad gas cause it started this right after I fueled up.

 

[caseypayne69]

gdawg- could be the o2's also. the car runs in open loop for the first couple minutes till the sensors warm up then it switches to closed loop and all the emissions kick in.
paul- after you swapped out all those sensors did you unplug the batt to reset the puter so it starts with all new inputs.

Im going through an idle issue my self. My plugs and wires are good and my MAS, TPS are good. Fuel pressure is fine. My IAC was messed up and I replaced it. Yet I'm still havin idle issues when I crank it. For every 10 times its cranked, one of them it idles rough with an engine light. Kill the motor and crank it, and its fine again. I think its PCM related for me. Clean your MAS maybe?

But my cars not throwing any codes... I'm even suspecting bad gas cause it started this right after I fueled up.

 

[realitygt]

still haven't figured this out... but did figure out that the bassani clamps aren't worth a shit, I have 5 exhaust leaks on my catback....

could an iac in any way cause a misfire?

 

[vermilion]

those clamps being jacked up could cause a surge like stumbling. id def change the wires and plugs. clean the iac while your under there. egr valves are tricky but normally cause more erratic symptoms and throw codes for several parts.