My 1997 Explorer is having issues. Planning on using it to go to Galveston and I need it to go back to Victoria Monday morning.


I got in this morning, drove about 5 miles to HEB and it was fine. Put 1/2 tank of gas, got it washed. Drove through the parking lot and parked it.

Driving out, no issues. I turn onto the Beltway to head home and if I hit the accelerator and the RPMs go past 1500-1800, it starts going 1500-700-1500-700 (rapid rise/fall).

I circled back to HEB and undid the air line connector to the Throttle Body. Pushed the throttle body with the screwdriver and it does the same thing.

I tried different gears; no difference. I was able to go over an overpass and get up to 55 MPH, so I don't think it is a ****** issue.

I ran the Torque app and I noticed the timing was a bit early; around 25 to 20 degrees TDC. If you pushed it too much, it would go negative. I could keep the throttle to about a max of 28%; above that and it would start the rev cycling again.

Did get a pending P0320 code (misfire). Plugs and wires changed about 10,000 miles ago


No noticeable smells/sounds. Idles perfectly. Drove back from Victoria last night (157 miles) just fine. HEB gas station is a common place I fill up (Summerwood HEB).



Any thoughts on the culprit of why it is going nuts now?


~egon

My first thought is maybe some bad gas? Second is maybe some water somewhere it shouldn't be from car wash?

When something goes wrong, I always think what was the last thing I did that could cause it...?

Thought that as well, but it idles perfectly. Just when you accelerate.

I unplugged the camshaft position sensor, I think, and plugged it in. I can now go to 2200 RPM before it starts surging/stalling. It did for a bit stay at 3000 in the driveway.

I'm thinking it is that sensor, but not sure of getting it off.

I had a truck from a client that came in once with a similar problem.

Idled fine, and when you drive it, it would fall on its face/stumble.

Had a tank of watery gasoline.

So, starts fine, idles fine, goes from a stop fine, but goes nowhere at highway speeds when you give it gas to pass? My truck did the same thing and it was the cam shaft sensor. Not sure about your Exploder, but the part was cheap in my truck. Getting to it was a different story. If you're able to get to yours, I'd try replacing it and see if that helps.

cam or crank position sensor was my first thought.

Didn't put diesel in it did you?

Id check thw gas before anything. Get some
Out of the fuel rail into a (dry) plastic bottle and see what it looks and smells like

No. I ordered a camshaft position sensor.

I recently (late 2015) changed the crankshaft position sensor. That will not let you run at all on this car.


Only issue is the CSP is on the back of the engine; between the engine and firewall on the passenger side.


I pushed the connector back in and if I do that, I can get the engine up to 3k RPM no issues. I drove to Petco to get food; driving there was fine. Popped a 3,000 RPM and about 45 in the neighborhood. Driving back, it started acting up again. Could get up to 45 without too much issue, but getting above 3000 RPM it would start bucking. Let off the gas, and slowly bring it up, back to being fine.


Hopefully this is a 2 hr fix and I am back in business.

How would I test the gas? Push on the fuel rail Schrader valve to collect some and see if it separates?

~egon

Yep

Or disconnect at fuel filter and turn key to run.

Have you considered it might be time to get a "new to you" vehicle?

Does the engine have coil over plugs? Check the rubber insulation to the spark plugs, and replace it if you see ANY cracks or wear. This caused misfires in my 4.8L mustang.

I have a brand new car ordered; it is supposed to ship today.

But 2 weeks for delivery and it is going to Austin.

~egon

Turns out it was the Camshaft Position Sensor.

And for the 3rd time I want to find the engineers of the 4.0 OHV engine and kick them in their naughty parts.

I have 2 Ford Official Manuals ($300 IIRC). Half the size of a f'ing encyclopedia set (2 binders). The info/pictures are 100% useless.

It covers 3 engines, 4.0 OHV, 4.0 SOHC and 5.0 OHV. For the sensor, they used the same f'ing engine picture; the SOHC. Where the sensor is on top of the valve cover, driver side, in the front. A 5 minute job, literally.

Mine?


You take the Upper Intake Manifold off (and 15 sensor/Jesus clips) then HUNT. You know the sensor is attached to essentially an old school rotor. But where.....?


On the back of the engine. Next to the firewall. Being 6' 6", I can bend/reach most parts of the engine. I had to sit on top of the engine. Rebuilding the engine I didn't have to do that. But for this $30 sensor, I had to.


But I guess after 20 years, it was time to go out. Best part is I dropped the old on and it never fell to the ground. So it is sitting on my ****** or some part of the engine (spent 20 minutes trying to find it). It'll either melt or be sold with the car.

~egon

Dr. Doctor said:

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I have a brand new car ordered; it is supposed to ship today.

But 2 weeks for delivery and it is going to Austin.

~egon

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What did you order?

2017 Pacifica Touring-L