There is a area at the end of an 02s life where it won't throw codes but it's hurting MPG. If they are only $35 for your truck just replace them both to rule that out.

Otherwise.. it would have to be something dragging like a brake.


Rich

 

Sounds good,

Ive got a few pictures here of the flap in the front end of the truck that covers the A-arm. Do you guys know the proper placement for these? they usually rub my tires so as you can see in three of the pictures it is neatly tucked in between the A-arm. The other picture shows what happened when i tried to tuck it in... It popped out and got all crooked..

Thanks!

 

Mine rubbed from the factory. Bigger tires chewed them up. So I cut off the offending appendage.

 

With a redone head gasket, new intake, new plugs/wires, and new O2 censors, I'm averaging 20. Same everything as you, 1999 4.0 OHV Auto Ext. Cab 4.0 w/ 3:73gears.....except I have 31" BFG AT's that chew up a little MPG.

 

Hey Steven what plugs and wires did you replace with? I wish I got 20mpg!! I was also thinking of getting the stock MAF housing to see if my port job is causing issues...

 

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So after months of more gas guzzling I am finally going to get new plugs and O2 sensors.

I was just going to buy the cheapies here:
http://www.rockauto.com/catalog/x,ca...,parttype,5132

Should i just go with the Denzo's? I take it there are only two sensors? left, right? I see some say upstream and downstream.. I have no idea what they mean there..

Also anyone have experience with the extreme performance autolite iridiums? they are only a little bit more expensive should I give them a try or the double plats? I mean who wouldnt want "extreme performance"!!

As for the wires at 44K miles I think they would be just fine, I was going to get a pack of conductive paste for the end of the plugs and call it good.
Looks like rock auto has these for $19 I would think they are worse than whats in there tho.. AUTO EXTRA Part # 26684 {ProGrade}
Bosche are only a little more and Standard Motor Products but I have never heard of them either...

Thanks!

 

Also, do I have to worry about getting different spark plugs for each side of the engine?

I thought I read something somewhere about EDIS but that may have been for newer rangers. I cant recall.

Someone also mentioned I can have my O2 sensors tested, can that only be done at a shop?

 

Bump

 

make sure your front end is alligned close. i got the same problem after working on the front brakes and rear end an my passenger front was sidetracking. fixed that and replaced air filter, plugs, wires etc. and was getting 24mpg highway till i fish tailed into a culvert a month or two ago. now i think my rear is bent on the passenger side. and the funny thing is since ive owned my truck the only damage that ever happens is on the dang passenger side lol. ill have to get pics for that side and driver side :D

edit. ford also has for some odd reason a factory induced sidetracking front end. possibly to help tire companies and oil companies idk but im bout to take all the electric sensors out replace the engine with a carborated one and fight back the big businesses

 

I will check on the sidetracking..

But disaster struck today!! I spent most of the day installing a new cold air intake.

Its basically a removal of the top of the air filter box and installing a small adapter to put the cone filter on the end.

Here is a photo of the intake:


As soon as i finished with the install I noticed the engine running very rough. then it smoothed out, then it was great! Then a start later.. The check engine light came on and it seems to be guzzling the gas!! Not running too badly but not perfectly smooth either..

Any ideas? Just cleared the PCM and did the idle learn, no light yet but its still soon, if it comes on again I will take it in to have it read. Please also note my MAF housing has had the porting done (cut out the extra pilar inside the housing).. Not sure if that the issue here, I dont know why the truck would fight this so badly.

Thanks!

 

Just got the codes read. Both banks running lean.. Is there anyway to fix this? Please let me know.... Ideas?

Also, I noticed that on some starts the truck bucks a little bit. I know plenty of people with high flow intakes this is wierd!!

Only thing I can think of now is faulty sensors, or the ported MAF housing. But I noticed Jet performance makes a housing exactly like mine (after mods) for 300$!! So apparently it works with the 4L.

 

Wow it almost sounds like you need to just get rid of that gas guzzling truck, i know that doesnt help you at all

 

I have thought of that but I love the truck and it cant be that complicated... Can it!? In the Higher RPMS it runs great and the bucking seems to be related to when you first start it and not all the time...

 

can you smell the gas when you start it up then make it roar a bit? sounds like your idle air flow sensor is going bad. lol also had to replace a wire on that come to think of it. pull the sensor then try starting it. if its running the same then the sensor is prolly bad. if it gets worse then the sensor isnt. my 4L has been actin funny with the cold and hot weather spurts. it runs great after 2-3 days of solid cold then a warm day hits and runs like crap. then after 2-3 days of warm weather it's fine.

 

I think you need to get the stock airbox and maf just to be sure its not the maf, and if its not then I would check the IAC, like stated above. In your case I think you need to return the MAF to stock just to be sure thats not the issue, then you can go from there.

 

Hey Vince, did you mean the Mass air flow sensor? I didnt know there was a idle air sensor.. The IAC should be fine, cleaned it about a year ago. Only 44K on the clock..

Phillip, the problems actually began as soon as I put the high flow intake on. I will try it to be sure but I can almost guarantee you if I put the stock air box back on it will be just fine. But of course the restrictive Fram tough guard filter will be back as well along with more 14MPG's crap...

I was going to try and find a stock MAF housing and see if that helps but that will take some time. And I would prefer not to drop unnecessary money on that..

If it is running lean is there any issues to running it that way? I would think it would help the MPG's anyhow. Its apparent my engine doesnt like all the air im giving it. It should be Thanking Me!!

Update:
I just put the stock airbox back on with the Fram extra guard filter. It is running much better now. Still something is strange... If you rev it in neutral to say 3-4K and let it go back to idle it goes real slowly back to about 700rpms running a bit rough then goes back to 900 or so and stays fairly smooth. maybe something is still out of whack? I thought about guy a junkyard MAF to see if thats what bugging out..