newb intro

Hi,
I am 3rd owner 98 explorer 4.0L SOHC. Have had the truck for about 12 yrs with no major work except the intake manifold recall (serviced). Truck only problem has been at 32-34 mph runs rough, any other speed not noticeable.
replaced p/s pump couple weeks ago, told by service it was my ping noise.
Has 171k on it, got it at 84k.

Welcome to this forum! Do you have any trouble codes? Did you clean the mass air flow sensor?

BrooklynBay,
thank you, no I haven't. the last time was about a yr or so ago when Precision Tune cleaned throttle body, and all, plus ran intake cleaner through engine using fuel line giving alot of smoke.

does it require the "CRC Mass Airflow Sensor Cleaner" spray or is intake cleaner ok?

Use mass air flow cleaner on the MAF sensor, and intake cleaner in the intake which is oxygen sensor/fuel injection system safe.

Welcome!~

Welcome to the site

Tony

thank you for the welcomes.
I just did what I could to clean the MAF sensor, it has a sealed unit except for I believe it own small intake port, so I sprayed the cleaner in there. It has one tamper proof torques screw and one that has either a covered top or no top, I didn't know how to get the one out without visegrip needle nose so I left I mounted. removing the air filter cover and the metal canister the sensor is mounted to did not give me access to properly clean the sensor. what can I do now? what I did spray didn't change the idle at all.
Russell

Check this link: http://www.explorerforum.com/forums/showthread.php?t=259038

I removed the sensor and spray cleaned it fully. It runs a little better. I have since been to an experienced mechanic who read the computer codes a P1260 clearly said the key was going bad and activating the anti-theft shutting off the gas; lucky not fully yet. I swapped the key with the spare. It is a lot more responsive, however the idle is still rough, the truck shakes some when the idle dips, but, it revs up quicker and regained "passing gear" the downshift and rev-up is much better. It starts on first try. Why didn't the dealer see this code? The only other was P0137 I think, which is the O2 sensor after the catalytic converter, a little old, but, still in the history.

Getting better, BUT!

BrooklynBay,

I have now replaced the PCV valve and checked/cleaned the EGR valve (not clogged).
I still need help, at 1000 rpm it is relatively smooth, but at 1500 it is much rougher. I have done a lot of the maintenance and only some improvement. I have no check engine light. Please tell me what is next. I also added a seafoam yesterday.

Did you check the fuel pressure with a test gauge? How old are the spark plugs & cables?

fuel pressure and plug wires

About six months ago the fuel pump died and was replaced, I think the filter was also; I have replaced the filter myself several years ago prior to this failure.
I don't know what the pressure is, but, I think I can check it. The plugs and wires were replaced in february or march for vehicle inspection sticker.
My induction timing light show all six wire getting spark from the coil pack(the distributor is retangular with 2 rows of 3 wires.

Rkcameron

found vacuum leak

BrooklynBay,

I rechecked the hoses for the PCV and found a hole rubbed in the driver side line, and smoothed the idle still more with the new hose. It is still a bit rough at idle and while I drive it. How do I use the fuel pressure gauge? I will check all the plugs and wires for looseness, or compression leak at the plug. I hope you can help find my tick/click sound whether it is one or both of the timing chain tensioner 'bolts' or the earlier timing chain guides. Do I need to smoke test for further vacuum leaks?

thanks,
rkcameron

did smoke test

The smoke test showed major lead on intake manifold gaskets (more than one place) and leak at and in the break booster and master cylinder. while it is apart the mechanic will check and replace bad hoses thermostat and gasket and incidental they find.

After intake gasket replace

Had the intake manifold gasket replaced, the master cylinder and brake booster, also the thermostat housing and thermostat with bypass hose. Engine almost normal !! there is still a ticking/clink (sounds like light metal) sound I can hear at idle and when noise it low while driving. Mechanic said oil pump intermittent shaft doesn't get enough oil and squeaks. I know it drives the oil pump. I am using seafoam to clean out sludge to see if there is something clogged, oil change soon. But, can someone comment and point me in the right direction to fix it? I was quoted $180 to replace oil pan gasket. I think its high. Is it?

rcameron

Maybe it's the timing chain or the tensioner?

timing chain

BrooklynBay,

I was hoping not to hear that. Do you ever replace the tensioner(s) without doing the timing chain(s), gears and/or guides? I see on 1AAuto there is a kit with all the parts except any gaskets or seals. Is there a test to determine which it is?

rcameron

Everything should be replaced at the same time. I suspect that this might be the issue since it has high mileage, and these engines are notorious for having timing chain/tensioner issues. Ask the mechanic what he thinks.

thank you