98 Explorer 5.0 poor idle

At first was hard to start, but will now start but idle poorly (almost stalling, then smoothing out repeatedly). Also lack of power on acceleration.

I poured my monthly can of B-12 Chemtool into the gas tank a couple of days ago - I've never had problems before doing this in over 230K miles.

Pulled the IAC and cleaned it...no change.

Pulled all plugs and cleaned them...no change.

Pulled codes P1504 (Idle Air Circuit) and P0153 (O2 Sensor circuit slow response; Bank 2 Sensor 1)

Any ideas of where to look next?

Vito

Reply to
Vito
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On Wed, 20 Sep 2006 16:25:48 -0500, Vito rearranged some electrons to form:

New IAC.

Reply to
David M

Your problems are classic for a bad/dirty IAC. They usually do not give a code for being dirty other than lack of throttle response during diagnostic scanning. Since you have an IAC circuit fault and the symptoms are there, I suggest your next step is a new IAC - forget cleaning. Also, clean your MAF sensor. There are numerous sites with pics on the net on how to do this. If you have not already, replace your PCV valve and make sure you replace the filter under the PCV valve. It is located in the top of the block behind the right rear of the intake manifold. You will need long needle nosed pliers to extract the filter. Damn sure not easy to get at but highly recommended to help prevent blown seals and oil pan gaskets which are even more of a bitch to replace on your Explorer. A new O2 sensor is the only cure for the O2 sensor code. IIRC, that would be the one in the left bank. You should replace both as a matched pair. These are also recommended maintenace interval items even if most folks don't bother - many don't bother with maintenance at all since it is only one more way the dealers have to screw their customers (TIC).

AS far as checking plugs, you are pretty much wasting your time unless you are getting a misfire code or you have arrived at the recommended change interval. When you replace the plugs, stay away from the Bosch plugs - the Ford and GM vehicles I have had did not like them. For about the same money, you can use the recommended OEM Motorcraft replacement or the Autolite plugs with good results. A spark plug can only ignite the mix one time no matter how expensive or how many fancy electrodes it may have. Anything it does beyond that is of no use. Use only the recommended type plug at the proper gap specified on the decal in the engine compartment unless you have modified the engine.

Lastly, why a can a B12 every month? Can't you buy decent gas in your area?!! It is not often that injectors need attention because of clogging unless you are using poor quality fuel. The major brands in the US blent higher than required levels of these additives to maintain the fuel system in clean operating condition. I am not a fan of constant additive use unless a good quality fuel or lubricant to do the job is not available.

Regards

Lugnut

Reply to
lugnut

Sounds pretty good Lugnut. Going to Autozone to get the IAC Valve and the O2 Sensors. I'll also inquire about the PCV Valve since I still have the original in place.

I was wondering about your comment concerning the B12 I pour into the tank monthly...primarily for water removal and cleaning of the fuel system. Do you really think it's a waste of money, and that fuel quality is that good?

Anyway, I'll post the results of the fixes this afternoon.

Thanx to all respondents.

Vito

Reply to
Vito

Also check for an open vacuum line. That can cause these sorts of problems.

Mark

Reply to
Nemisis

If you buy your fuel from a reputable station that sells a reasonable volume, the chance of getting water are remote. I have gotten wet loads of fuel a couple of times resulting in fuel filter blockage - they generally will restrict or prevent the passage of water if they are saturated with fuel before the water gets there. I am not familiar with the ingredients of B12 but, if it is water you are concerned with, something with ethonanol may be what you are looking for. Also, fuel tanks have been pretty much seal in recent years reducing the tendency to collect water by condensation. That said, I do keep an additive with ethanol around just in case I pick up a load of wet fuel that causes problems. Beyond that, I don't worry about it.

Lugnut

Reply to
lugnut

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