Would bad spark plug wires cause this? 96 explorer 4.0

[porshapower]

I am chasing a problem and am running out of ideas. I have no check engine light on but there is something not right. At idle the truck does not have a smooth idle. There is stumble (miss) in it. Its not severe and you cant even see it on the tach but you can here its slight popping out of the exhaust as its happening. I have replaced the plugs,Iac,egr valve,egr pressure sensor,cleaned the maf sensor,cleaned the throttle body,new airfilter. The truck accelerates perfectly and only stumbles at idle? Would spark plug wires cause a symptom like this? Also did the "seafoam" through the brake booster vaccum line. Ran techron fuel cleaner and tried different fuels. The explorer is a 5spd and I can see the shifter handle and feel it shaking from the non smooth idle. Wouldnt wires cause a misfire all the time even at acceleration? Thanks!Nel

 

[jimbo74]

yes, could easily be the plug wires

 

[HappyGilmore]

yep my idle did the same thing, and especially under acceleration there was a miss. i replaced the wires with ford motor craft wires and it fixed the problem. when i replaced them with autolites (before the motorcrafts) it only fixed it for about 2 days then came back. so i returned them and bought motorcraft. no probs since.

 

[porshapower]

yep my idle did the same thing, and especially under acceleration there was a miss. i replaced the wires with ford motor craft wires and it fixed the problem. when i replaced them with autolites (before the motorcrafts) it only fixed it for about 2 days then came back. so i returned them and bought motorcraft. no probs since.

Mine only does the stumble at idle. Under easy or hard accelerations its fine. You still think its a possibility? Thanks

 

[jimbo74]

yes... i replaced my dads plugs on his ranger... well at idle it idled fine, but under acceleration, it ran like crap... runed out the boot was torn, and it sat flat at idle but the higher voltage under acc cuased arcing

 

[porshapower]

yes... i replaced my dads plugs on his ranger... well at idle it idled fine, but under acceleration, it ran like crap... runed out the boot was torn, and it sat flat at idle but the higher voltage under acc cuased arcing

Hello I have seen this happen but mine is backwards. At idle its stumbling and under acceleration perfect. I figured with more acceleration there should be the same or more resistance and it should do it as well?

 

[HappyGilmore]

well have they ever been replaced? if not then i would suspect them.

 

[jimbo74]

hello yourself.... yes it can still be spark plugs, i was jsut relating it to my experience... my boot was torn, and sometimes it was fine, sometimes it wasnt

 

[Aussie Explorer]

So it will not miss under light or heavy acceleration and will only miss at idle. Correct?

How about when you are cruising at any speed that has the RPM above around 1500 will it miss then and if so will it then register on the tacho??

If it is only missing at idle, that would really surprise me if it was just the leads it would be very strange if it is doing it at idle it should do it at speed as well. Look for burn marks (Arcing) on the leads especially where they are close to one another. It generally will not be notable during heavy acceleration depending on how bad they are but cruising is a dead give away. (Change them regardless).

I would also be looking at the crank angle sensor; this can also cause problems if dirty like erratic idle.

Also dirty injectors
Fuel filter
Ignition timing
Low cylinder compression

And as engines get older and part’s where they do develop some roughness to them, as you say it is not even registering on the tacho,If you look at the engine can you se it stumble, (It will like kick side to side as it misses) .

 

[porshapower]

So it will not miss under light or heavy acceleration and will only miss at idle. Correct?

How about when you are cruising at any speed that has the RPM above around 1500 will it miss then and if so will it then register on the tacho??

If it is only missing at idle, that would really surprise me if it was just the leads it would be very strange if it is doing it at idle it should do it at speed as well. Look for burn marks (Arcing) on the leads especially where they are close to one another. It generally will not be notable during heavy acceleration depending on how bad they are but cruising is a dead give away. (Change them regardless).

I would also be looking at the crank angle sensor; this can also cause problems if dirty like erratic idle.

Also dirty injectors
Fuel filter
Ignition timing
Low cylinder compression

And as engines get older and part’s where they do develop some roughness to them, as you say it is not even registering on the tacho,If you look at the engine can you se it stumble, (It will like kick side to side as it misses) .

Hello and Thanks for the reply. Yep only at idle. If I cruise at any speed it wont do it. I am going to try wires then go from there. Dont think its injectors I ran techron through it 2 times and seafoam the other day. Will keep you posted on the outcome with the wires. Thanks! Nel

 

[live2_4x4]

Change the wires

My 94 did the EXACT same thing that yours is. I cleaned the MAF replaced the IAC, replaced the plugs, replaced the fuel filter, cleaned the injectors, tried premium gas, new air filter, retorqued the intake manifold bolts, seafoamed, and aside from a truck that ran great any time it wasn't idleing it didn't help a bit. Finally after running out of other things to try I replaced the plug wires problem solved. Hasn't returned since. I would describe the problem I was having as a popping noise at idle not visible on the tach, and if you gave it any gas at all it would go away, let it drop down to idle again and after a few second delay, pop,pop,pop away it went. Try the wires let us know how you made out.

 

[porshapower]

My 94 did the EXACT same thing that yours is. I cleaned the MAF replaced the IAC, replaced the plugs, replaced the fuel filter, cleaned the injectors, tried premium gas, new air filter, retorqued the intake manifold bolts, seafoamed, and aside from a truck that ran great any time it wasn't idleing it didn't help a bit. Finally after running out of other things to try I replaced the plug wires problem solved. Hasn't returned since. I would describe the problem I was having as a popping noise at idle not visible on the tach, and if you gave it any gas at all it would go away, let it drop down to idle again and after a few second delay, pop,pop,pop away it went. Try the wires let us know how you made out.

Changed wires..no luck. Changed coil pack..no luck. Will be living in this truck soon I think Ive got a good hunch on what it is. When I stand over the driver fender and rev the accelerator,I hear was sounds like vacuum coming from behind the egr vacuum wire area. Its coming from under the black thing on top of the engine that says 4.0(intake manifold?) I have reached down inbetween its round tubes and cant feel any vacuum lines down there..I see the injectors. Its the same sound as having a large hole in the rubber intake hose and sucking air.

 

[410Fortune]

there are simple ways to find a vaccuum leak. Soapy water, ether,

try a search on this forum.
Sounds like a classic vacuum leak
Stop throwing $$$ at it.
Coil packs RARELY go out, if ever and are expensive to replace.