being cranky when it gets alot of moister in the air. about 4-5 weeks ago it was foggy my truck was running at idle like it had a HUGE cam in it right around 250-300 RPM ran like crap the next day it was dry and snowing it ran fine idled at 550-600 where it always does so i said ok. this morning i start it when leaving my g/f's same issue and bad to the point where i could smell and see raw fuel in the snow out of each pipe.

got some terminal cleaner cleaned off the part that plugs into my coils *New not even a year old MSD coil packs* then put some dielectric grease on them. then took each wire off of the coil only and did the same thing sprayed some stuff then put some dielectric on it. still ran like crap would not even stay running. i pulled my air filter and cleaned the MAF i relized a rubber boot to the TB was loose tightend that up no change. at this point i was frustrated so i got it to start and held it at 2,500-3,000 RPM then after about 30-45 sec of that it cleared up.

i let it stay there for a few and it stayed fine let it go down slowly it stayed at a good idle i went out in front and started spraying vac lines to hear for a change heard nothing. then i heard what i think is the IAC valve open and it started running like crap for about 10-20 sec then it idled fine.

im leaning towards ign stuff but its almost as if somthing clicks on and poof it runs like crap but only when its foggy or alot of moister in the air. on a dry day or when it snows it runs fine. Also i put some Ford racing 8MM wires on not very long ago. but i think its more than 1 wire because ive had this thing running on 6 and 7 cyl with no prob i think it is a whole coil pack the way it is running and throwing raw fuel out of both pipes.

ideas?

 

considering that you double check the connections to the COPs or coil packs and that they are relatively new COPs/ coil pac...ordinarily this hints of weak COP/coil pac.

I would remove the whole throttle body housing (TBH), and give it a good cleaning...the IAC should come off with the TBH & is easier to remove & clean the IAC then. Also with the TBH there is 2 internal EGR ports that like to get carboned up, so get those cleaned out too.

Use carb cleaner on the TBH and good ole WD40 on the IAC. With IAC there is a small rod inside that NEEDs to move freely.

Make sure that the relays for the ignition coil pac/COPs are not warm...if so replace them too.

from there clean the MAF sensor....& if it still doesn't improve then change the fuel filter and then test the fuel pressure.

 

well got it to throw a code P1121 TPS sensor A inconsistent with MAF sensor and PO175 system too rich bank 2.

i unpluged my MAF and the truck ran fine idled fine everything i plug it back in and back to crap. i had a MAF off a 1997 Expy with a 5.4L thought oh it will just bolt on....wrong the housing is a diff size. so i took both MAF's to work because they have the safety torque's bits heads on them and the one off the Expy had one of the bolt heads epoxy so you could not get it off... well i got it off with a pair of channel locks *the bolt* got it out

i noticed the out of my truck was a Ford Mo Co sensor and the one out of the expy is an NGK put the NGK one in my housing threw it all back togther when i just got home from work and it idle's smoother than ive ever heard it run. guess 176,000 was enough on my factory MAF.

hope this fix's the prob.

Thanks for the post enriched.

 

well i guess that didnt fix it either. got up a few mins ago for school and it will not stay running again.....

 

well i took the batt off for about 30-40 mins and it started up and seemed to be running fine i took it on a quick trip around and seemed to be running ok then when i came to a stop the truck shut off. started right up and jumped to 1,200RPM and died again. started it up put it in drive real fast and gave it some gas kept it running. then as i let off to turn into my driveway bam dead again. the stumble seems to be gone but it wont run at idle.

also i have an aftermarker oil press gauge and the oil press seemed to be lower than normal. i have a TPS i think i may replace that tomorrow.

 

you certainly can try a new/different TPS ,can't hurt if you have the spare parts lying around...still willing to bet its the IAC all gummy, & or, the EGR ports internal to the throttle body housing are plugged... & at 176k on the ticker is is due. A lot of folks consider this good maintenance, doing this every so often. and it sounds worse that it is...2-3 hrs taking your time.

certainly couldn't hurt to double check for vacuum leaks too.

 

i deletetd my EGR a long time ago. i cleaned my IAC right around 120,000 when i was having plug issue's im starting to lean towards the IAC as well because it will run fine if i keep my foot with the throttle open then when i let it off it idles ok for 5 seconds then its almost as if somthing turns on and bam its dead.

 

Had the same problem you describe a few weeks ago. I changed the plug wires and that corrected it. Runs fine now in all damp weather. I checked the resistance for each wire and they were in spec, I assume the jackets were faulty. Replace your wires, these trucks like to eat them every 2 years or so.

 

TPS or IAC. My truck did exactly the same thing minus the moisture issue (good ole PHX). I replaced the IAC with a generic and it ran like shiest...Motorcraft IAC next and it ran fine. Went through the same trial and error with my TPS when that acted up...all Motorcraft for me. With the EGR delete it seems like an IAC problem or odd O2 readings

 

while running fine try tapping the maf with the plastic end of a screw driver a few times all around. If it effects the idle then it is the maf. That''s how I found a bad maf on a chevy from the 2.8L mpfi engine. Hope you get it fixed.

 

well the IAC and my TB where both a little on the dirty side. i cannot get the TPS off the screws are frozen in there pretty bad.

 

well threw it all togther it seemed to idle fine it died once out on the road started it got the RPM's up and threw it in drive and it ran fine got 5 gallons of gas seems to be running fine. i have a CEL not sure for what yet. but i think cleaning the TB and IAC may have done the trick.

 

well last night as i started my truck to leave work at 2:30am and it was running like crap just like before. i unpluged the MAF and it ran all the way home just fine. got up this morning and pluged it back in and its running fine.

 

I have never had much luck with cleaning an iac. I was having idle issues recently, cleaned the iac and it worked ok for a few days and then started to hard start again. Bought a new one at AZ, problem solved.

 

well i shot the messenger and not the real prob...

i kept thinking why when i unplug it does it run ok... pull the MAF harness and sure enough there was a few chunks of bare wire showing on it.

took it to work had my boss fix it runs like a champ now.

goes to show to check the simple stuff first ha