Im actually posting for a friend. Im working on his mothers explorer (for free). Seems she has no clue, or at least not at all observant.

Anyway, they come to me and tell me the tranny is slipping. I immediately notice the SES light on. I decided to check codes to see if I have any errors coming from the tranny. So far I have these codes: P0455 P1151 P0304 P0174

I dont know this vehicle at all and wanted to see if some of these items are common and/or possibly related to each other.

Heres what I have found:

P0455 - EVAP leak somewhere. Seems a lot of people have discovered a crack in the filler neck.

P1151 - Passenger O2 LEAN

P0304 - Cyl 4 missfire

P0174 - Passenger lean condition "A Heated Exhaust Oxygen (HO2S) sensor indicating lean at the end of a test is trying to correct for an over-rich condition. The test fails when the fuel control system no longer detects switching for a calibrated amount of time."

Looks like I need to clean the MAF, check vacuum leaks, possibly replace passenger O2. Ive also read some of these codes come from a common issue with the intake gasket. May need to replace it? How should I clean the MAF? Can I use some normal solvents?

Any input would be greatly appreciated.

TIA

EDIT:
Also, I need to mention a tick/tap on pass side under cold idle (consistent, but not constant). Still need to test to see if it happens at other times. Right now has Seafoam in the oil and about to run it and then change the oil. Also, have ran it though the brake booster. Currently in the sit and wait process, about to go out and make the neighborhood smoke like Hiroshima.

 

Heres something I found looking up the Cyl 4 missfire:

A #4 misfire is fairly common on 4.0L OHV's. The intake manifold to head gaskets are notorious for vacuum leaks but they can also fail in a different way and leak a small amount of coolant into the intake runner causing misfire. This is almost always on cylinder #4, occasionally on #1

Looks like its deffinately all related to an intake gasket failure. I want to know if its the plenum gasket or intake gasket. I show both of these on autozone site. Not sure which to get.

 

OK, got the intake off. Gasket was destroyed. The rubber piece around the coolant jacket, by cyl 4, was almost completely deteriorated. All the intake rubber gaskets were completely flattened and I'm sure did nothing. The upper plenum gaskets were also completely flattened (actually less than flush) and without a doubt in my mind were sucking in unmetered air. I will be getting some Hylomar gasket maker (safe around gasoline and even recommended as intake gasket).

 

What you need is a full intake gasket set. Depending on the year you can go with either Fel-Pro or Motorcraft. If your model has the full metal intake, the Fel-Pro is better and cheaper. If yours has the plastic upper intake, the Motorcraft has been updated to fix some issues, whereas the Fel-Pro is based on an older design.

I would not use RTV of gasket maker. The problem with those such things is look at what happened to your original gasket. It dried out and compressed right? An RTV gasket is gonna dry out and compress much faster under engine heat than a neoprene gasket will.

 

Thanks for the input! But you should really check out the properties of Hylomar. I can deff see that the intake gasket is a bad design. Actually I think the whole damned engine is a bad design. What were they thinking when they made this thing?