Hi.
I have a 96 Explorer 4.0,automatic, 61,000 miles. I have a problem that is driving me nuts! Here it is, The engine idles very rough when up to operating temp. on hot days. It runs fine in the cool evenings but not in the daytime!!! I can also feel it running rough at highway speeds in cruise control around 1800 rpm.I replaced the usual, plugs, wires, fuel filter, checked vacuume lines. The problem seemed to occur when I changed the plugs so I changed them again with autolite platinums, no improvement.Then I thought I may have damaged a wire, so I changed them, no improvement. The check engine light dosen't come on. So what can it be ? Any help would be greatly appreciated
Thanks
Ken

 

You may want to clean the EGR valve, throttle body, and ASC motor on the engine from any carbon build-up. The ASC motor is a metal cylindal with two bolts and 1 wiring harness on one end. I clean mine about every 15,000 when I change the oil, etc. It should help smooth the idle out some, but if you have a real rough idle, you have something else wrong...

Sounds simple, but also check to make sure all the wiring harnesses are plugged back in after you work on it. Have missed a plug before myself and know it can happen.

Good luck...

 

I have a similar problem, did this get resolved ?

Thanks,
Paul

 

I have the same problem on my 1991 Explorer 4.0l V6. When it kicks into overdrive and the RPMs are under 2000, the engine runs very rough. New plugs, new wires, new Ignition Module, new Fuel Pressure Regulator, and cleaned the MAss Air Flow Sensor.

One thing that helps is taking the battery power off for an hour or so to reset the computer. Then the tranny doesn't shift into overdrive at such a low RPM. Within an hour of driving it though that changes and same problem.

What does ASC mean and where is the ASC motor? The only components on the intake manifold are the Throttle position sensor and the air bypass valve.
There's an Air Charge Temeraure Sensor on the valve cover I haven't touched.

 

Found one of the culprits of my rough running engine. I pulled the spark plugs when the roughness was at it's worst and discovered the number 5 cylinder is getting oil in it somehow and fouling the plug. This URL pointed me to the problem. See the section submitted by Murray H. I also have some oil consumption, and this explained it.

http://www.glue.umd.edu/~singletn/web/pages/ping.html

 

 

I've been having similar problems with my 95! When I start it up for the first time it runs fine until it reaches operating temp. Then it stars to idle rough and if I let it sit and idle for a while then put it in drive or reverse it bogs down almost stalling! Sometimes it does stall. Starts right back up but if I'm not on the gas it almost want to stall again. After driving for a while I would have to let it sit for at least 5 or more hours to cool down. If I start it up any time sooner than that it barely wants to run sometimes stall right away after a very weak start. Over the past few months I've changed several parts; spark plugs, fuel filter, egr valve, egr dpfe, egr vacuum solenoid, air intake temp sensor, air filter, coil pack (last year), and still can't figure out what the problem is. Got an obd1 scanner (Innova 3145), ran it and came back with codes 114, 327 and 335 and that's after I changed all those parts. CLUELESS!!!

 

It's been awhile since I've looked over the ignition system diagrams for a 1995. The symptoms you describe are similar to what would happen when the ignition module was faulty on Fords around that era. The modules were mounted on the distributor and as they heated up, connections opened up (probably bad solder joints) and the engine would misfire and sometimes stall until the modules cooled enough for the joints to again make contact.

Does your 1995 have an ignition module?

-Rod

 

When was the last time the O2 sensors were replaced? Once the engine goes into closed loop operation, the O2 sensors come online. If they are faulty, they will cause poor idle/stalling and driveability issues.

 

My truck is distributorless, I have a coil pack. I took the throttle body off to clean it and noticed that the upper intake plenum had a small puddle of fuel inside it. I replaced the pressure regulator earlier this year.

 

Both o2 sensors were also replaced earlier this year

 

my ford almost stalled again today, still trying to figure out what's wrong! check engine light came on too so I put the obd1 scanner on it and came back with these codes. Any insight???

<table align="center" border="1" width="87%"><tbody><tr><td>114
</td> <td> (O,R)
</td> <td> </td></tr></tbody></table>
<table align="center" border="1" width="87%"><tbody><tr><td>335
</td> <td> (O)
</td> <td> </td></tr></tbody></table><table align="center" border="1" width="87%"><tbody><tr><td>327
</td> <td> (O,R,M)
</td> <td> </td></tr></tbody></table><table align="center" border="1" width="87%"><tbody><tr><td>177
</td> <td> (M)
</td> <td> </td></tr></tbody></table><table align="center" border="1" width="87%"><tbody><tr><td>173
</td> <td> (R,M)
</td> <td> </td></tr></tbody></table><table align="center" border="1" width="87%"><tbody><tr><td>113
</td> <td> (O,M)
</td> <td> </td></tr></tbody></table>

 

I'd look at the connection in the large harness plug in the engine bay under the air intake coming off the filter housing... See if you have a broken retaining clip that isn't holding it together tightly. Had that happen on a buddies 94. Can your scanner run the wiggle test?

 

I believe my scanner can run the wiggle test

 

I ended up changing the tps and pcv valve, drove it around for a while then ran the code reader again and got an 111 code. So hopefully the problems are solved! I will give it a few more runs though before I am completely sure that it's running correct. On the tps, the spring loaded part that connects to the throttle body was only spring loaded in one direction, the other direction just spent kinda freely, no resistance at all! Where as the new one was spring loaded in both directions. The pcv valve was crap also. Keep ya posted!