slight miss under load after installing plugs and wires

[green streak]

I'm normally good at diagnosing these problems, but I need some help with my 95' 351 powered Bronco. I changed out the plugs and wires dist. cap and rotor button about a week ago and now I have a noticable miss when under a load in overdrive when pulling hills. It also does it with the overdrive off when pulling a trailer. It idles fine, goes through gears fine and otherwise runs like a champ on level ground. I checked the gap on the plugs before the install. Rechecked all the wires after the install and they are all where they're supposed to be and look good. I replaced the fuel filter yesterday thinking that it might be my problem, but the miss is still there. Also scanned codes and came up with the "111" everything is fine code for both running and key on/ignition off tests. The check engine light has never came on. I've ruled out all my possibilities without taking it to a real mechanic. I'm still thinking it's something with the spark, but it could've been there before but multiplied after the tune up I guess. I've looked my work over 4 times now, except for pulling the plugs, and all seems good. Suggestions are certainly appreciated. Thanks in advance, Jeremy

 

[Devil Dog08]

I'm normally good at diagnosing these problems, but I need some help with my 95' 351 powered Bronco. I changed out the plugs and wires dist. cap and rotor button about a week ago and now I have a noticable miss when under a load in overdrive when pulling hills. It also does it with the overdrive off when pulling a trailer. It idles fine, goes through gears fine and otherwise runs like a champ on level ground. I checked the gap on the plugs before the install. Rechecked all the wires after the install and they are all where they're supposed to be and look good. I replaced the fuel filter yesterday thinking that it might be my problem, but the miss is still there. Also scanned codes and came up with the "111" everything is fine code for both running and key on/ignition off tests. The check engine light has never came on. I've ruled out all my possibilities without taking it to a real mechanic. I'm still thinking it's something with the spark, but it could've been there before but multiplied after the tune up I guess. I've looked my work over 4 times now, except for pulling the plugs, and all seems good. Suggestions are certainly appreciated. Thanks in advance, Jeremy

i too had a problem like this b=4 and it turned out when i bought the plugs i did not check the numbers on all the plugs and here when i pulled them out two of the plugs were different .

 

[green streak]

i too had a problem like this b=4 and it turned out when i bought the plugs i did not check the numbers on all the plugs and here when i pulled them out two of the plugs were different .

My next step was to pull the plugs out again to take a look and re-gap them, but me and 30 degree weather don't get along too well. :lol:

 

[AdamDude04]

I too just recently had this problem as well.. going up a hill, in overdrive.

I just drove out from Denver to Sacramento (1,200 miles) in 20hrs.. and I noticed after salt lake city going up those long inclines and through the salt lands my truck too would have a slight missfire that wouldn't throw a code, but you could barley feel it. Truck sounds normal/runs/idles fine.

89 with 302

 

[green streak]

Well I just drove it again and it feels more like a surge than a miss. I'm going to buy some Lucas, put some 93 octane in it, and drive it like I stole it hoping it's just a dirty injector, because I'm not pulling plugs again until I can get it inside somewhere or until it gets above freezing again. Thanks guys.

 

[miesk5]

yo

Check plug wire routing; according to the diagrm on top of radiator and/or in this;

Misfiring/Pinging due to Improper Spark Plug Wire Routing

94-96 5.0 ** - INCLUDES 5.8 - engine miss, spark knock, buck/***** surge and other driveability concerns

Source: by Tank92 (Tank) at SuperMotors.net http://www.supermotors.net/clubs/superford...ry/media/299011

Spark Plug Wire Routing & Firing Order TSB 94-04-10 for 87-93 5.0 & 94-96 5.0 & all 5.8 - engine miss, spark knock, buck/***** surge and other driveability concerns

Source: by Ford via Steve83 (Steve, That dirty old truck) at SuperMotors.net http://www.supermotors.net/clubs/superford...ry/media/470416

 

[bobstrat]

my 95 with the 351 has been doing the same thing, though it seems to occur when the truck is cold.

if i figure it out before you do i'll post it here.

 

[Krafty]

have you guys tried gas line antifreeze? its cheap and an easy way to rule out freezing in the fuel lines.

 

[bobstrat]

have you guys tried gas line antifreeze? its cheap and an easy way to rule out freezing in the fuel lines.

it hasn't really been cold enough here yet for that to be an issue for me.

this isn't so much a reply for you, as it is for green streak.

 

[billmcg]

I've been having the same problem with my 89', did the same thing you did, new: plugs, wires,cap, rotor plus new ecc relay and ecu on the dist. I still have that same "miss", however I was talking to an in-law who happens to be a ford mechanic, he told me that the fuel rail on these motors is teflon inside and after a few years the teflon breaks loose and clogs the injectors. Says all I got to do is remove the fuel rail and injectors, backflush every thing and soak the fuel rail with a strong solvent, then flush again. His suggestion on the injectors is to get one of those square 6v batteries with the spring posts to open the injector and blow some cleaner backwards thru them (do this quickly so as not to ruin the injector). Now I really like the guy and he is a ford mechanic, so i'm pretty sure he knows what is up, i'm going to pull the fuel rail in the spring and drive it sparingly till then, however on the injector cleaning, i'm not sure about what it would take to ruin it power wise. Does the battery thing sound feasable?

 

[green streak]

Thanks for all the replies so far. You guys rock. I haven't driven her in about a week, but I'm leaning toward the problem that Miesk5 posted up. It makes the most sense so far, especially since the problem didn't start until after I changed the plugs and wires, and I've smelled an electrical burning smell after every time I've driven it since the plug wires were changed. I'm gonna re-arrange them according to the diagram (if they aren't already) and see what happens. Should be an easy fix if that's my problem. Thanks everyone.