2002 explorer sport trac P0171 , P0174

[jonenitro]

I have searched this forum and others up and down. This is my problem it starts hard when cold and i get a po171 po174 code this is what i have done so far if someone can help it would be much appreciated.

1) changed air filter
2) changed fuel filter
3) checked fuel pressure its at 69 book says 65 +8,-8 it is in range
4) changed plugs and wires auto lite platnum with motorcraft wires
5) chnaged intake o-ring gaskets
6) cleaned mass air with crc mass air cleaner
7) cleaned throttle body and iac sensor
codes keep comming back
i have a autoxray 6000 which can capture data and get freeze frame data if it helps
my next choice is to change mass air any suggestions
thanks in advance
jonathan

 

[jasonl]

I had a 2002 Sprt Trac that had a stumble at idle. It was very noticeable and annoying. Check your MAF reading at idle and see what it says. If I rember it should be around 5.5 volts(verify this)???? I could be wrong. Does it idle nice smooth?? Anyhow mine would only set a random misfire code. I ended up finding the foam gasket at the MAF where it bolts onto the air box by the filter had been sucked into the air tube partially. I removed it reinstalled and put some sealant around it to be safe. Cleaend my MAF and it was fine after that. Good luck.

 

[wahlstrom1]

Might wanna try searching for a vacuum leak via propane/ether, as a leak after the MAF may lead to a lean condition which could throw those codes. I know the OHV 4.0 are notorious for leaking at the gasket between the lower intake and fuel rail, but I'm not sure about the OHC.

 

[jonenitro]

i had sprayed arround with carb cleaner wd-40 and finally eather and found no vacuum leaks. i changed the gasket between that you mentioned also the six orings because i noticed that every one suggested that. i did them last weekend with no help code came back within 10 miles i am leaning on changing the mass air flow sensor. hate to waste $120 if it doesnt fix it though. i also forgot to mention i checked the pvc elbow and changed the pvc valve with a factory motorcraft one when i did the intake gaskets. thanks for you help .

 

[wahlstrom1]

That sucks to hear....I replaced my MAF first and lost the $220 before finding the problem. Sorry I couldn't be of more help....

 

[jasonl]

Do you have any driveability problems?? It would seem odd to have a p0171 & p0174 with a perfect running vehicle.

 

[jonenitro]

none at all it runs fine hard to start first thing in morning very rough idle for about 30 seconds to 1 min have to give it gas then its fine. once warm starts fine drives fine

 

[Jspafford]

Sure sounds like an IAC problem to me. Wife's 02 did the same thing.

 

[jonenitro]

would a bad iac pull them codes? i cleaned it seems to be working ?

 

[jasonl]

Check your tube where the oil breather goes into the air intake tube as well as the elbow from the oil breather by the oil fill. I have seen both of them swell and cause a vacum leak. If you don't have a vacum leak I would guess yor MAF.

 

[jonenitro]

well i bought a mass air meter installed it with in 15 miles light came back on now what ?????????? guy at advanced auto let me return it saved me 200 bucks. that was a break

 

[jasonl]

It is showing lean on both banks so I would doubt you would have a bad injector on each bank. You eliminated the MAF, you have to be getting unmetered air into the engine somewhere. Did you check the rubber intake tube and breather hoses as I mentioned in my last post?? Start at the MAF and spray carb cleaner any where and everwhere , even on the air filter tube all the way to throttle body as it could be rotted/cracked. If it is turning the light on that fast it must be a sizeable leak.

On my old ST the shop never installed the PCV correct and it basically created a reverse vaccum in the PCV system. It sucked oil out of the breather hose at the oil fill and into the air filter tube causing the tube to swell and create a vaccum leak. I also had the gasket around the MAF that I told you about earlier.

 

[jonenitro]

yeah i will check that stuff wendsday since it will be 50 outside i had doused the everything i thought could leak i will try agian though my wife had got in a acident on passenger front near air box about a year a go im wondering if it has anything to do with it i did only minor damage hood,bumbercover and headlight wonder if it messed anything up
thanks for your help and i will get back with my results.

 

[jonenitro]

you were right weather got better and i was able to check it agian Well i found a bad vacuum line the elbow next to the radiator hose had a big crack hope this fixes it will no soon