Mighty Max Help.....
 

Well, the ole gal finally gave up the ghost, about 400 miles after she turned 325k miles old......and I need some help.

I drove it to work yesterday, and all was fine. When i left to go to school, it was running a little weird, a little low on power. Got to Moncks Corner, and it was a little more sluggish. When I left school, it was worse. It was super slow, and would bog down if I floored it. It was running fine, other than the sluggishness, no noises or skipping or anything weird other than low on power. I also noticed that it was burning gas WAY more than normal.

Got to 526 and it got really bad, but I had to get home. Wife and baby home sleeping, and I had to work at 5AM so I pressed on thinking it was a bad catalytic converter (seen this before). I made it to Duncan's boat harbor bridge and I had to pull over. It wouldn't go over 50 MPH and didn't want to go up the hill. I unbolted the cat on the side of 526 and it was the same so i got a ride home.

Read on a forum about there being a cat INSIDE the exhaust manifold taht would cause this, so I went back to the truck today and pulled the manifold and gutted it. Put back together and same deal.

It will idle really low, but when given gas it just gets worse, and won't rev up. So I had it towed home. Changed the fuel filter and same deal.

I have changed plugs/wires/cap/rotor, cleaned MAF, fuel filter, air filter, gutted cats, all to no avail.

Any advice? Where to start? Thanks :cheers

Injector

Or bad gas?

Fuel pump

does the engine sound normal when spinning over or does it drag. it sounds like you have a fuel problem with the gradual loss of power unless the motor is slowly locking down....

FP or MAF bad

See below

Sounds fine, and has since this started

I'm gonna play devil's advocate and stupid at the same time with the fuel issues. If it was filter or pump, it would be starving for fuel, correct? It has been doing the opposite. I burned 6+ gallons of gas from North Chuck to monkey corner and back, at least twice what it usually does. Can you explain to me how it would use MORE gas if it was a fuel issue? I'm really stumped on this one.

I cleaned the MAF to no avail.
Is there a way I can test it? Unplug it and it doesn't change either.
Not to mention a reman MAF is $169 from rockauto.....wtf?


O2 sensor...would it do this?

Thanks again guys, I'm stumped at this point.....

i cant see it being the o2 sensor.

Or maybe it has a stuck injector and is flooding the motor so it has no power.

id almost bet on there being something wrong.

Any way to check this??

Lol ya don't say!!

If it has too much fuel, there is a simple solution. Inductionsolutions.com, and get yourself a dry setup. I bet itd get up that damn bridge...at least once.

ive heard boiling injectors will fix them but id try it as a temp fix. if they are easy to pull google how to do it and try it. worse case scenario it dont fix it

Private Gump, you're a freaking genius.

siphon some of the gas out so there wont be as much

That's weird, never heard that. Here's a thread

http://m.ls1tech.com/forums/showthread.php?t=1235851

Sounds like a maf or maybe even tps issue.

It definitely recognizes throttle changes, but something is keeping it from responding to them.

Check fuel pressure and make sure the fuel doesn't have air or air bubbles like if a fuel rubber fuel line is cut in the tank. It might need a pcm also

check the plugs...It will tell you which cylinder is your problem

Take the 500 lbs of vidio and computer equipment, bumper guards, spare Mossberg, and cage out.

You too?

I still bet it's injector related.

ill throw my 2cents in.....a symptom of a bad fuel pump is bad gas mileage.....im leaning towards a fuel pump....esp w 325000 miles

Just a joke. Someone was gonna say it.

My first guess is the MAF, I had my dad's Toyota t100 do the same thing you are describing and after gutting the cat I got a MAF from LKQ (they can hunt you one), and it's been going for him ever since......

2nd: Fuel pump. My Silverado pump is going out and I'm getting terrible fuel mileage.

3rd: Injectors

same thing happened to my friends truck a couple different times and it was always the mass air.

Would unplugging the MAF make any difference in the way it runs? Should it run a little better that way?

Is there ANY way to test the damn thing?

It'll run like poop without it, best way is to just swap it out. There should be plenty floating around on the interwebz forums.

There aren't "plenty." There are some remans going for $160+......hence the reason I asked.

Would really hate to buy one and it not be the issue. Guess I need to go junk yard shopping.

It's the same MAF as in all of these other vehicles that utilize the 2.4 4G64 motor, there are TONS of these cars so you shouldn't have a problem finding one.

1991 - 1999 3000GT
1993 - 1994 EXPO LRV
1992 - 2004 DIAMANTE
1994 - 1998 GALANT
1996 - 2005 ECLIPSE
1990 - 1996 MIGHTY MAX
1993 - 1995 EXPO
1992 - 2000 MONTERO
1990 - 1992 D-50

I believe the Sebring/Stratus had the same motor as well.

Freakin' mitsubitchy expert I tell ya!

Lol, spent a lot of years working on them, I've had 2 4g63 cars and 2 4g64 cars with the same motor as the mighty max.

Lkq $26 is what I spent on maf for the eclipse that I got to flip.