1995 Ford explorer XLT 4.0L v6 Rough running

This is the first time I’ve used this discussion site. I have some major problems with my explorer. The idle is rough and accelerating is rough also. If i nearly put it to the floor it almost seems like it studders the power. it will feel great for a second than feels like its less power for a second than more and less and more and less. When i’m sitting at idle, it will idle fine than after a minute or so it will bog way down and shake the whole vehicle. when that happens i give it some gas and it comes back to normal idle than it does it again after sitting for another minute. I’ve replaced spark plugs, wires, alternator, oil change and some tires.Ive been told by many mechanics it could be the IAC Valve or the fuel pump or the fuel filter or a vacuum leak. I’m pretty sure its one of them but before I get anything replaced i want some professional feedback. Please respond if you have any useful advice asap.

Is the Check Engine Light lit up?
What can you tell us about the vehicle’s maintenance over the past 3 years?

I dont know how its been maintained. I know the person who owned it before me was a mechanic who works on stock cars and he said he replaced the fuel injectors and head gasket. I’m assuming he also did his own oil changes. The check engine light is not on and has never come one for me except for one time when the alternator went out

“The check engine light is not on and has never come one for me except for one time when the alternator went out”

Are you sure that the CEL isn’t burned out?
Does it turn on (briefly) when you turn the ignition key?

Regarding maintenance, I wouldn’t assume too much if you have no maintenance records.
It will be much easier to accurately diagnose the problems if you first bring the vehicle fully up-to-date with maintenance, which probably means replacing the spark plugs & plug wires, the air filter, the fuel filter, the PCV valve, and the trans fluid.

I don’t know if the '95 Fords were put together with OBD2 or not. If so, you should still take it somewhere (Autozone, Advance Auto, etc) and have them scan it anyway. You could have some passive codes that might give you some insight as to what is going on.

As far as vacuum leaks…a vehicle that age can definitely have some bad vacuum lines. When the engine is completely cold (hasn’t been ran for several hours), have a can of carb cleaner ready and start it. Spray around your vacuum lines, around your air intake, etc. Do quick short bursts, don’t soak anything. If you have a leak, you’ll notice your idle speed will change noticeably when you hit the affected area with carb cleaner. If you find leaks, fix them…if not, take that same can of carb cleaner and use it to clean out your throttle body. Remove your IAC valve and see if the plunger moves freely. It would be a good idea to clean it out as well.

Does your vehicle have a MAF (mass air flow sensor)? It will usually be between your air filter and throttle body, in the air intake system. It will have an electrical connector hooked up to it. These can get dirty and drastically affect performance. If you have one, it wouldn’t hurt to take it off the car and spray the inside of it with AND ONLY WITH “mass air flow sensor cleaner” it’s only a few bucks at any automotive store (or Wal-Mart). Most of them will have a honeycomb mesh type insert and the actual part that takes the reading will be somewhere behind it. Do not touch the sensors with your fingers. Just spray the hell out of the internals with MAF cleaner.

Sometimes a clogged fuel filter will only give you performance issues when accelerating or anytime you’re demanding more fuel. At idle, it’s not as noticeable.

You could also add some Berryman B12 to your fuel tank. It’s extremely potent, so make sure you fill up completely after adding.

Also does it have a distributor cap & rotor setup? Might be worthwhile to remove these as well and check the contacts underneath to see if they are burnt/worn down/etc. Check the rotor, too.

thanks for all the feedback. VDCdriver, I have replaced the wires and plugs. I’ve also replaced the mass air flow sensor and yes billfrank85 i’ve used the mass airflow cleaner. It does good but doesnt seem to be the issue. My mechanic has checked for vacuum leaks. I went to replace the IAC valve but it was the wrong kind of iac valve but when i took off my old one it seemed to be a little dirty but dont believe there was any mobility problems with it. And my mechanic has done a scan on it with a newer scanner but said that he could not read any codes. Eventually he had got into some of the codes (not all) but it seems like the only issues that he saw from the partial codes was my ABS. And to answer your question VDCdriver all of the dash lights turn on when i go to start it than most of them turn off beside my abs light because i have an abs line that is apperantly snipped and the seatbelt light if im not wearing my seatbelt. And also I believe I do not have a distributor.

Just to clarify, does this problem only exist at idle/low RPM and does not occur if the pedal is say at least half floored?

You might try unplugging the MAF sensor and giving it a quick test drive. The CEL will probably come on and leave a MAF code but that’s not a worry. It will go away and this is only a test.

I’m not sure on your Ranger which system you have as 1995 was a midway year from OBD1 to OBDII. If the latter is in place on your truck there should be a connector by the steering column under the dash. The earlier system diagnostic link is generally under the hood and consists of 2 connectors; one resembling a flattened house and the other a single pin connector.

okay you lost me talking about the connectors. But you are correct ok4450. it only has problems in low rpm really. But i’ve replaced my MAF sensor, and it didnt seem to be the issue. And what do you mean by “test” if i unconnect the MAF sensor and its the same than what? And if its different than what? Like the reason why I use this disscussion site is because honestly this is my first vehicle and I dont know what it could be.