99 Discovery II bucking

[discomike]

Don't use K&N cleaner, if you are going to try this first have it tested, you don't know for sure that it is bad.
If it is failing, go to Radio shack or some electronics store and get some contact cleaner.
The Maf sensor is that piece between the air filter housing and the air intake tube, if you look at you picture you will see a wire harness plugged into it.
Unplug the harness and remove the the Maf, if you look inside the tube you will see a small wire assembly that senses the air, that is the target. Clean the inside of the tube and that wire assembly and let dry completely before reinstalling. You might want to inspect and or replace your air filter at the same time.
Remember only do this if you confirm the fault code first, also it is slightly less then a 50/50 chance it will work and if it does, you will still have to have someone with a scanner or a test book clear the code and reset your check engine light cause it won't go off by itself.
By the way, what area do you live in, the picture of your truck and the houses behind it looked familiar?
Mike J.

 

[tree25]

Ok.. to make sure I got the right part, this is the MAF sensor circled in red on my engine pic right?

Ok.. also I don't know jack about cars, what and where are all these plugs that I need to replace? I keep hearing on here get 8mm plugs. I have no idea what that means? are they difficult to replace? I know virtualy nothing about cars, but I fix and install phone systems for a living so I'm pretty good with my hands and I hope I can figure this car thing out..

Thanks for the tips Mike.. The area of that photo is in Suwanee, GA about 30 minutes northeast of Downtown Atlanta..

 

[discomike]

What you have circled is only the connection to the MAF which is that tubliar housing that the air goes through. You will need to unhook the 3 spring clips from the air filter box as well as remove the top of the air filter lid which is in the lower right corner of this picture. Once you have removed the air filter lid and unhooked the 3 springs you can see inside the MAF housing and see the wire sensor in question.
The 8mm plug wires I mentioned are for the spark plugs, if your truck still has the originial spark plug wires, they are really worn out and should be replaced. The factory wires are 7mm. in size some of the better aftermarket wires are 8mm. and last longer also giving better voltage to the spark plugs.
Mike J.

 

[Monty]

How does the air filter look?

 

[DiscoFever]

tree,
first off your maf sensor is located (using the pic for refference) just below the "accordian" section in the air intake hose, which runs up from the airbox. Another way to say it if you dont understand my slang is it is the top portion of the horseshoe-shaped wire/hose that connects to the large air intake hose, coming off of the airbox in the lower right hand corner of the pic...

now i think the problem may be electrical, more specifically your distributor, especially if the bucking is happening under loads or climging at higher speeds, IE the interstate.

this is a problem that i have had on other vehicles, I initially thought it must be fuel delivery, so i changed my fuel filter, but in fact it turned out to be a bad distributor cap. keep that in mind if you do spring for the dealership or indy garage. good luck

 

[discomike]

Tree doesn't have a distributor, his is a 99 with coil packs.
Tree, does the check engine light stay on, if not, the next time it starts to act up while your driving it, put you foot in it and drive it hard. Doing this while the truck is acting up and the check engine light is flickering will usually set a code and then you can go get it scanned and find out for sure what is acting up.
Mike J.

 

[tree25]

Tree doesn't have a distributor, his is a 99 with coil packs.
Tree, does the check engine light stay on, if not, the next time it starts to act up while your driving it, put you foot in it and drive it hard. Doing this while the truck is acting up and the check engine light is flickering will usually set a code and then you can go get it scanned and find out for sure what is acting up.
Mike J.

I took it to get the codes read today.. The service engine light was flashing the whole time I drove today.. It was a much better ride the first 15 minutes, but it struggled after that so cleaning the MAF was strictly for fun.. 5 codes came up on the autozone reader.. P0306 came up twice

P0306
P0306
PO300
P1319
P0305

 

[tree25]

P0306
P0306
PO300
P1319
P0305

anybody know what these codes mean? Am I screwed

 

[discomike]

Well there is more good news then bad.
#300 multiple misfires
#305 #5 clylinder misfire
#306 #6 cylinder misfire
# 1319 is an ABS code
So, lets getaway from the MAF and look at plug wires and then possibily a coil pack since both # 5 and 6 are fired from the same coil.
Go out tonight start the engine in the dark, open the hood and look at the plug wires, see if you see any arcing from the plug wires to the engine and get back to me.
Mike J.

http://www.spanishtrailrovers.com/Tech/Info/OBDII_Scan_Codes/obdii_scan_codes.html

 

[tree25]

Glad those codes aren't horrible news..

I assume the plug wires your referring to are the grey wires labeled 1-8 that are connected to the engine.. Wires # 6 and # 8 seem to have some spillage under them, there is some brown oily residue on the engine under where these 2 wires connect.. I can't tell that any plugs arch back to the engine, Plugs 1 thru 4 all look like they are all positioned as though they are being pulled towards the back of the engine, but I think they are designed that way for easier access.. By the way are these 8 grey wires the ones I could change and make 8mm wires? been reading a lot about that on here.. you can send me an invoice after she runs like new

now that I think of it all 8 plug wires might be arching back to the engine.. I'm not sure if the head of the plug connector is desinged like an L shape or if this is the arching you are referring to look for?