I have a 1996 Ford Explorer with the 4.0 V6. Engine was loosing antifreeze so pulled the motor down to lower intake. Replaced upper and lower intake gaskets along with valve cover gaskets. Put back together and now vehicle is running very rough and blowing lots of smoke. When the vehicle was pulled apart non of these issues existed. I have taken apart twice just to make sure all gaskets are in place and can't understand why this issue is happening. Is there something I missed? Any help is appreciated.

Ford Explorer 4 0L V6 SOHC P0171 P0174 Lean Codes Common Cause

where is such a simple word
where;
3.2L V6, SOHC head 6VD1 (not the 6vd1w twin cam heads)
x marks the spot
asked many time here, and same answer.
if you look , you see it, then see its not possible to get to the 2 rear bolts (telling you what?)
pull engine block, ? no
pull intake, yes.

REMOVE UPER INTAKE 97 EXPLORER V6 4.0 - YouTube

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https://www.youtube.com/watch?v=ugExJ0wkP8A
Jun 11, 2013 - Uploaded by Sum Guy
REMOVE UPER INTAKE 97 EXPLORER V6 4.0 ... I was told that all I have to do is remove the fan belt to get access to it ... FordExplorer 2000 intake manifold gasket upper lower P0174 by froggy - Duration: 36:54. by froggy 36,588 views ... Ford Explorer 4.0L SOHC Rough Idle P0171 P0174 Lean Codes ...

Putting the lower intake on my 1997 Ford Explorer 4.0 OHV ...

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https://www.youtube.com/watch?v=qKE1vPxqPHs
Jun 27, 2010 - Uploaded by origionaldz
Putting the lower intake on my 1997 Ford Explorer 4.0 OHV sport .... I do have a 2000 5.0 ... @michaelheiland123654 To dothis job, you have to remove the alternator, unbolt the AC compressor, remove upper intake manifold, remove fuel rail,remove all injectors, ... Do you have the SOHC or OHV version?

1999 Ford Explorer 4.0L -need assistance on removing upper intake ...

www.automotiveforums.com > ... > Ford > Explorer ' Explorer Sport Trac

Sep 20, 2011 - 1999 Ford Explorer 4.0L -need assistance on removing upper intake ...Are you sure you have the OHV/pushrod engine and not the SOHC engine? ... Do youhave the upper intake manifold loose, you just are unable to ... the lower intake gasket, valve cover gaskets, Injector o-rings, plugs and wires. Thanks ...

How to replace upper intake manifold gaskets - Ford Explorer

Have you adjusted the pushrods properly? Pushrods generally need to be adjusted after installation.

Not sure how to do this on this model, although I own a 94 Ford Explorer with the V6 4.0 Liter motor.

Basically, when a gas engine doesn't run, you check 4 things, and narrow it down from there.

1. Gas (Is gas pressure good, is gas flow strong enough?)
2. Spark (are all spark plugs firing properly? Is spark strong enough)
3. Combustion at each cylinder (timing, pushrod adjustment)
4. Air Flow (MAF/MAP sensor working? Air Filter dirty?)

Appliance Repair Utah

there is a tps located on the intake where the inlet tube for air intake connects, it would be on the left side of the throttle body. does the trk run rough on idle? up/down sputter sometimes stall? Is check engine light on? if no light,check all vacuum lines for cracks/splits loose fit. do this by spraying carb choke cleaner on connections motor rpms will change if leak is present. also spray around perimeter of intake housing where mates with lower intake if engine revs you have bad intake gasket.I Just replaced upper and lower intake on my 98 and shazaam, runs like it should. but do your checks first,unessasary fixes are costly and **** you off.

The loss of coolant, overheating and running bad could add up to coolant leaking into the engine. The Dexcool antifreeze used in the GM vehicles has caused gasket failures in the upper air plenum and the lower intake manifold. This could allow the antifreeze to be pulled into the combustion chamber and the oil. If there is no visible external leak, then this is probably what's happening. Sometimes the gasket leak will show up as a very small and difficult to detect puddle somewhere around the gasket/engine mating surfaces. Also look for signs of coolant in the oil. If it has gotten into the combustion chamber, then it has probably ruined the O2 sensors and catalytic converter. The only solution is to pull the upper and lower intakes and replace the gaskets. Change the oil and filter. DO NOT put Dexcool back in the radiator. Use a green antifreeze that is labeled compatible with aluminum engine parts and radiators. Replace the O2 sensor. The catalytic converter might have survived. Get it running first, then worry about the converter. Good luck to you, and try to have a Merry Christmas.

I believe the schrader valve for checking your fuel pressure can be seen looking from the passenger side of the engine. It is on the fuel rail, which is installed between your lower and upper intake manifold sections, about the center of the fuel rail.

Hope helps (remember rated this) Good luck.

ACCORDING WITH THE MODEL AND YEAR AND IF YOU HAVE A 4.6L ENGINE IS PRETTY COMMON LEAKS FROM THE INTAKE MANIFOLD TO THE CENTER OF THE ENGINE AND IS WHY YOU CANT SEE WHERE IS COMING FROM BECAUSE THE ANTIFREEZE RUNS TO THE BACK I RECOMEND TO CHECK THAT AND USUALLY YOU HAVE TO REPLACE GASKETS AND MANIFOLD BECAUSE THEY MELT DOWN ON THE UNION WITH THE LOWER INTAKE MANIFOLD(PROBABLY NEED TO REPLACE ONLY THE UPPER ONE)

The PCV valve for a 5.0L is located below the upper intake manifold in the rear. It is locate in the lower intake manifold in the rear right below the upper intake manifold. It is really hard to see but if you get a mirror you can probably see it.

If you have some common tools the knock sensors are no big deal.  If you take a lexus they will make is sound like you need to completely disassemble the engine and scare you off.
First, do you really have a problem with preignition causing real knocking due to carbon buildup, or diluted gasoline or do you have failed knock sensor(s).  Try to decarbon the engine first.
There is a technique used with water being sprayed into a warm engine intake.  This will clean up the valves and carbon buildup which can result in engine knocking.  

The job will be a couple hundred for the parts and a couple hours of your time.  After you are done, you have entitled yourself to approximately $500 in new tools for your tool chest since this is what Toyota and Lexus will charge to fix (about $1k+).

You will need to buy the following to address the knock sensors and a couple other items while you're in the neighborhood.
- 1x upper intake plenum gaskets - 2x lower intake plenum gasket - coolant bypass hose found in the same area as knock sensors - 2x knock sensors (bank1 and bank2) - short pig tail cable which connects both knock sensors to common wire harness. - toyota antifreeze  (2 gallons, if i remember correctly... when mixed to 50/50 (antifreeze/ water) you will have 4 gallons.
drain the radiator drain the front of the engine using the engine drain plug - this plug is on the front right side facing the engine, behind the right hand exhaust manifold. (this will lower antifreeze enough to avoid dumping antifreeze all over the engine later) remove the air filter box remove the connections into the throttle body remove the cable from the throttle control remove the upper air intake plenum remove the two lower air intake plenums remove the antifreeze fill port
Knock sensors will be in the valley between the lower intake plenums.  You will need to remove the rubber antifreeze bypass hose (little short hose blocking access to the knock sensors).
By the way, the reason you bought a replacement, is that if this short hose splits from normal wear, you need to spend this money and effort to reach it, so just do it now.
The little pig tail cable which connects both knock sensors to the wire harness is said to cause a big majority of the problem due to the plastic getting hot and brittle, falling off and shorting to the engine.  While in this mode the engine thinks knock is occuring and starts to retune the air fuel mixture to get rid of the knock until it goes into minimal operations mode.
After replacing the knock sensors (and tighten to torque specs), replacing pig tail cable, and reinstalling your new short by pass hose.  Replace the lower gaskets, antifreeze fill port, lower intakes, upper gasket, upper intake, air intake, air filter, reattach everything, reconnect all the rubber lines you pulled off, make sure there are no splits in the air intake passage anywhere, retighten the engine antifreeze drain plug, and the drain on the bottom of your radiator, and your done!
Don't forget the easy stuff.  Dilute the antifreeze with water and fill the radiator and overflow tub.  Run the engine for several minutes until its hot and opens the thermistat to allow antifreeze into the empty engine cavities.  Turn the engine off and get a cold one as the engine cools.  Once absolutely sure engine is cold, refill the radiator with antifreeze and refill the reserve tub.  Do this at until all the beer is gone and you are both full of antifreeze (in one form or another)..... obviously red stuff in the car, amber down the gut.