Rough idle and acceleration

[Dylansav]

Hey I'm new to this site but I bought a 1998 Explorer V6 4L XLT about a month ago and runs really nice and has about 119K mi on it.

But I've noticed that whenever I start it up, the RPMs jump up to 2500 and than level off at 1000. I don't know if this is normal or not. Also, when it's idling, it sounds kinda rough. It sounds like it's pulsating or something, almost like the RPMs are jumping up and down even though they stay level when idling.

Another thing is whenever I accelerate it sounds really rough and I can feel the vibrations on the gas pedal, but I think this is probally tied with the idling problem.

We're thinking that we should start off with replacing the fuel filter, air filter, and replacing the spark plugs.

Thanks in advance if you guys could help me out.

 

[mechjames]

with the high idle, it could be a vaccum leak, or a dirty IAC valve

 

[ThePhoenix]

is your check engine light on?

 

[BillyBob82]

I had a similar problem recently. Turned out to be a bad injector. See if it's throwing codes first

 

[aldive]

I would definately check the IAC valve.

Good luck ...

 

[Dylansav]

thanks for the replies guys

We just replaced the IAC valve, hasn't changed a thing, still has the rough idle... We also put in a new air filter and a belt (making a squeak)

I'm going to bring it in for a tune-up though at a garage nearby, I talked to my buddy and he says that it might be the plugs or a dirty fuel filter.

For the injector, is there anyway you can replace one yourself or does it involve tearing up the engine? I've tried some of that liquid injector cleaner (not the cheap stuff this time hehe..) and it didn't do much.

For the acceleration, I found out that my front left tire and back right one were both really low on air...got that fixed

thanks again

 

[MadExplorer93]

Buy some SEAFOAM and put about half of it into a FULL tank of gas and run it till it gets to a quater of a tank left. If you have a dirty or clogged injector SEAFOAM is very good and cleaning them out. If it improves the condition then i suggested getting a second bottle of it and do the whole procedure again to help clean them out some more.

Of course it may take you a weel or so to burn all that GAS, but depends on how often you drive and how far you drive, but either way just do as i suggested to see if it cleans them out.

Now take the other HALF of the bottle and unplug the Brake Booster Line or the Vaccum line for the Crusie Control if you have Cruise Control and allow the SEAFOAM to be sucked into the Plenum while the MOTOR is warmed up do this, not when it is cold.

Once it is sucked up you will notice SMOKE like blue smoke/brown smoke coming out of the Exhaust which is OK and Normal as that stuff will clean out the Pistons and Hopefully the Bottom of the Valves.

Now a word to note on is that the PLUGS may become fouled in some vehicles that SEAFOAM is used on, but the majority don't. If this does occur, clean the plugs or replace them.

To replace an injector you will need to pull the plenum off and the FUEL rail is under it, this requires you buying the Gaskets for the Plenum Two Gaskets in all and on some models there is the O-Rings under the Plenum. You should also change the O-Rings on all Injectors as why not since you have it torn down already. You will also need the Thottle Body Gasket.

 

[Dylansav]

Where can you get some of this SEAFOAM? that sounds like a possible solution to this, hopefully I won't have to get at the injectors myself though, from what you described, seems like a week long job for me haha

 

[MadExplorer93]

Napa Auto Parts in Canada Sells it, so look at Napa in the USA or AutoZone, call places like those or try Wal-Mart which we call Wally-World in my town.

 

[aldive]

Where can you get some of this SEAFOAM? that sounds like a possible solution to this, hopefully I won't have to get at the injectors myself though, from what you described, seems like a week long job for me haha

Advanced Auto Parts carrys it.

 

[jman_07]

Wow this is identical to what my explorer is doing i understand the pulsating you are talking about does it shake a bit at idle as well mine isnt idleing well at all. IAC has been replaced hope to find this issue mine pulsates but rpm stays the same and when mine starts it shoots up to about 2k As well rough start it takes forever to drop as well.