Rough Idle and Engine Surge Under Load | Ford Explorer Forums - Serious Explorations

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Rough Idle and Engine Surge Under Load

ERUSH97XLT

Well-Known Member
Joined
October 9, 2008
Messages
236
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City, State
Omaha, NE
Year, Model & Trim Level
01 XLT, 03 XLT, 13 XLT
Hello!

My 97 Explorer (4.0L OHV) has a confusing problem:

1. It has a rough idle only under a cold start. Once the engine warms up (or is started warm), the idle smoothes out.

2. The engine surges, sputters, and skips under load.

3. The "Check Engine" light is NOT on. I know it works.

What can this possibly be?

Thanks!
 



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Clean the Mass Airflow Sensor, the throttle body, and the Idle Air Control and see if the idling problem goes away.

Welcome to the Forum
 






can you here a vacum leak under the hood maybe check that the pvc vaulve is still securley in place
 






Thanks for the advice guys!

I'll check it all out and get back to you :)
 






Ok.... I took the mentioned components off/apart and cleaned them thoroughly with throttle body cleaner (NOT carb cleaner). I also checked for vacuum leaks; none were evident.

The initial startup seemd fine. No rough idle, sputtering, or other abnormalities.

A short, normal-condition test drive didn't yield any skips, surges, etc.

I had similar results trying to resolve this issue when I reset the computer by disconnecting the negative battery cable, but the simptoms returned after a few days. This time, I'll give the engine a few days to reset itself before pursuing any further solutions.

Thank you so much for your help! I'll reply to this post if the symptoms return.
 






What did you use to clean the Mass Airflow Sensor?
 






Oops! forgot to mention that.....

I had a can of CRC's "MAF Sensor Cleaner" left over from cleaning my old ranger's MAF sensor. Seemed to work just fine.
 






Ok good. I was praying that you didn't use throttle body cleaner on it. That wouldn't have ended well.
 






Yeah, I learned that lesson the hard way :p:
 






*sigh*

The rough idle and sputtering/surging is back! What could this possibly be? Could a sensor be faulty and the "Check Engine" light isn't coming on? I double-checked for vacuum leaks both with a gauge and starting fluid. Any other suggestions?

Thanks!
 






The next thing I would check are the spark plugs and the plug wires. I am having trouble coming up with something else that would only make it run rough when hot.
 






The next thing I would check are the spark plugs and the plug wires. I am having trouble coming up with something else that would only make it run rough when hot.

Just to clarify, the engine runs rough only when COLD, not hot.

I thought something might be wrong with the plugs or wires, too. I already checked the ones on the driver's side (they're the easiest to get to ;) ) , but I'll check the others, too.

At one point in time, I had similar symptoms (except the rough idle was at all engine temperatures) and a spark plug was broken (yes, I romoved it in pieces). I wonder if that goofed up the whole engine for good.

I'll check the remainder of the plugs and wires and get back to you.

Maybe I should squirt some seafoam in the intake and see if that helps? The throttle body and IAC were pretty gunky, so who knows what the rest of the intake its like....

Thanks!
 






intake gaskets

Hi,
yesterday I have changed the gaskets of my intake system.
I had rough idle when the engine was cold before, now it runs very smooth.
The old gaskets especially the lower set where as hard as stone. When i prayed them out of the seats they just break into pieces!
The new set cost about 40 euro here in germany,
changing took me about 3 hours, and I'm no professional. I guess I have seen a how to do in this forum.
Regards Andreas
 






Ok. I checked the spark plugs and wires. Nothing out of the ordinary. I re-gapped the plugs according to my Haynes manual (0.054") just to be sure. I think the "Check Engine" light would come on if there was a major problem here (i.e., misfire, circuit fault, ignition coil circuit fault, etc.)

No change noticed. Here are some more specific idle and surging characteristics:

The engine idles at 1000 RPM. Is this high? I mean, my old '93 Ranger (4.0L OHV) used to idle smoothly at about 500 RPM.

The "surging" and "skipping" occurs around 2000 RPM whenever the engine is under load (i.e., climbing hills, smooth steady acceleration while maintaining 2000 RPM) in any gear and at any temperature.

I'm "befuddled". The "Check Engine" light is NOT on, and I'm running out of ideas.

Any more suggesstions?

Thanks!
 






Sorry if this is obvious, but have you tried filling up with fuel at a different place than usual, or putting in a few gallons of premium along with a gas treatment product?

I had a similar problem over the weekend - filled the X up Friday, and she got really angry later in the afternoon. No CEL, no vacuum leaks, etc.

I put in a bottle of Advanced Auto Parts generic gas treatment and it got a little better but still wasn't running right, so I added a bottle of Chevron fuel system cleaner, and a few gallons of premium gas from a different station - fixed the problem.

I suspect there was some water in the underground tank at the gas station, which caused the ethanol to come out of suspension and when I filled up I got too much ethanol/water and not enough gasoline. :mad: :thumbdwn: 10% ethanol blend :mad: :thumbdwn:!!!
 






Thanks for chiming in, Bubba!

I usually run Valvoline's "Max Life" fuel system cleaner about every oil change (about every 3000 miles or 3 months), so I know my fuel system is clean (or at least I think it is...). I also use regular, 87 octane gasoline whenever possible. I haven't filled up with ethanol for a VERY long time.

I'll try premium fuel next time (from a different station), along with another bottle of cleaner and see what happens.

Thanks! I'll get back to you all!
 






Partially working DPFE or EGR

Surging under load is sometimes a symptom of a partial problem with the DPFE or EGR. There may be a stored code with a so-so DPFE even though your CEL is not on (ask me how I know - lol). Try to get your codes read. You can also do this simple test - unplug the EGR from the DPFE and and plug the vacuum hoses. You may get a CEL on startup, but ignore it and go for a drive and see if you still get surging under load.

- James
 






Wow this sounds like the exact problem I am having with my 96 5.o awd.

I bought some MAF cleaner but am a noob and am unsure what and where to spray down.

My cel is on p0446, p0171, p0174 for codes. If I clean the MAF per the p0446 code could that also clear the other two as a dirty maf could cause the engine to run itself richer?

**BTW- I DO realize that buying a manual would answer most of my questions but I just had a baby 5 weeks ago and money is very tight right now.
 






Surging under load is sometimes a symptom of a partial problem with the DPFE or EGR. There may be a stored code with a so-so DPFE even though your CEL is not on (ask me how I know - lol). Try to get your codes read. You can also do this simple test - unplug the EGR from the DPFE and and plug the vacuum hoses. You may get a CEL on startup, but ignore it and go for a drive and see if you still get surging under load.

- James

Thanks A TON for the input, James!

According to my Haynes manual, my symptoms and driveability issues may due too much EGR flow. I'll tinker around with the DPFE and EGR and get back to you.
 



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Make sure the gas treatment you put in "removes water". The problem with mine wasn't a dirty fuel system - it was just bad gasoline. All of the local stations here have 10% ethanol blends now - I can't find non-ethanolated gasoline anywhere anymore.
 






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