recently, i drove 30 miles in my 2000 explorer 4.0 OHVduring which the vehicle started dying at stop lights and the idle was bouncing from about 350rpm's to 1500 rpms. once i got the vehicle back to my barracks, i put new spark plugs(bosch platinums) and spark plug wires in it along with a new fuel filter. It still idled the same way while in park except it wouldnt die as much, but as soon as i put it in reverse or drive, it would just die. Could it possibly be the timing belt or maybe the MAF( mass air flow sensor)?

 

Could be your converter. When it's cold turn the engine on and go right to the tailpipe. Clamp your hand over the end of it. If it doesn't have enough pressure to blow your hand away you have your problem. Also a hot test the same except with a board instead of your hand will help. If it's a timing belt skipping for god's sake don't start it. Look to see if the belt is slacked bad or teeth are missing on it. I don't think an air flow sensor would make it just die out so fast (unless you're maybe running without an air filter). A speed sensor, jumped alternator brushor dirty battery cables could also be a problem. I'd check them last.

 

check temp sensor and thermostat, idle control valve? They fixed my similar problem.

 

I had a Similar Problem with a 4banger car.
it had started to idle erraticly and would just die if you put it into gear.
unless you held the throttle down some when you put it in gear.
then it would pull hard to about 3000 rpm and just cut out.
after many days of replacing parts, Plugs, TPS, IAC valve, O2 sensor,fuel filterect..
it ended up being a bad fuel pump.
even though it showed fine on a pressure test.
oh the joys of fuel injection computer controlled engines.
what I wouldnt give to just have a set of points and a carburetor again, lol

 

I agree. So many people end up getting old and on fixed incomes hooking up your car toa machine for $500 is out of the question. Then you're double/triple screwed when the tester can't figure it out (or the mechanic can't decipher it correctly).

 

lol, yeah, my 1979 nova was nice to work on, but this explorer is so nice, too nice to have this problem happen, i will check the fuel pump. Is it on the inside of the gas tank? im not sure, the only type of fuel pump i have messed with was a mechanical pump on my 305 in my nova.

 

Fuel injection pumps are usually in the tank. The more I look at it though - the less I think it's that. If it runs in Park - it could be low fuel pump pressure - but the pumps usually don't fail so easy. Plus it should run nearly the same in gear. It sounds like a transmission problem. Maybe a bad vacuum modulator, torque converter or filter. Could be dirt in the idle circuit. Have you checked the transmission fluid lately? (assuming it's automatic).

 

Low fluid will shut it down when it goes to go into gear.

 

Dude,
I know the problem exactly, it is the MAF sensor. Take it apart, spray it with electronic cleaner, (just the wire, looks like a lightbulb filament). Next, clean the Idle control valve, it is on top of the engine under the black plastic cover, same thing, clean it up with electronic cleaner, it will solve your problem.