2000 ranger misfire/stumble at idle n...

2000 ranger misfire/stumble at idle no codes

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Ravena, NY

#1 Nov 4, 2009
I have a 2000 ford ranger 4.0 4x4 since I bought it at 35,000 miles it has a misfire at idle. there are no check engine codes. about every 20-30,000 miles the #1 spark plug fowls out and it sets a misfire code. I clean the plug and the code does not come back but it still has the stumble/misfire at idle. I have thoroghly cleaned the injectors and have changed the plugs and wires. What could be causing this?

Homestead, PA

#2 Apr 9, 2010
Hi dusty. I am having the same problem and will be taking it to a good mechanic as soon as possible. This guy does not quit till the problem is resolved. i'll get back to you. Do the same if you come up with anything.
dusty wrote:
I have a 2000 ford ranger 4.0 4x4 since I bought it at 35,000 miles it has a misfire at idle. there are no check engine codes. about every 20-30,000 miles the #1 spark plug fowls out and it sets a misfire code. I clean the plug and the code does not come back but it still has the stumble/misfire at idle. I have thoroghly cleaned the injectors and have changed the plugs and wires. What could be causing this?

Homestead, PA

#3 Apr 9, 2010
Hi Dusty. I have the same problem with my 2000 4.0 4x4 ranger. I am going to take it to a very good mechanic to hopefully find the problem. This guy will not stop till he finds the cure. I'll let you know what happens. Please do the same if you come up with an answer.

Blairsville, PA

#4 Jul 15, 2010
About two months ago I installed Autolite iridium plugs into my 2000 ranger and so far the misfiring has stopped. It might be worth trying for $45.00 dollars.

Mystic, CT

#5 Oct 7, 2010
Dusty- I too have an 2000 ranger 4X4. I have the same problem and I can only say this. It is possible that you have a small head gasket leak. Are you adding coolant every couple of months? Are you changing either the plug or wire every couple of months? Does it only happen to misfire when it's raining? Does the truck feel when it misfires like the bottom end is going to fall out? It could be that you are fouling the plug out. I had to replace my plugs and wires because I've burnt the boot and the plug is fouled. For me it seems to go every three months, so I carry a spare with me at all times.

Phoenix, AZ

#6 Oct 9, 2010
*****It is possible that you have a small head gasket leak.*****

It could be leak in intake manifold gasket, head gasket or crack in the head. In my case it was head cracks in 3 cylinders right between valves. It caused intermittent misfires, until spark plug got busted from coolant on hot plug. Machine shops try to "pin" this king of cracks, but I don't believe in such a repair. Therefore, I didn't try to machine the head, and I didn't get rebuild ones or ones from junkyard: they ALL have cracks. It is just poor ford design: they started with 2.5L V6 engine and increased cylinder size until heads started to crack. You can get cheap aftermarket cylinder heads that are better than original (got more cast iron and better coolant passages... yes, casting is made in China, but what the heck, it ain't rocket science to cast iron to spec... chineese invented cast iron anyway...). That's what I did to mine and it's good for now (knock-knock-knock). Newer overhead cam 4L V6 are better for cracking: pushrods don't take up space and valves are better spread out.

Blairsville, PA

#7 Oct 10, 2010
How do you check for head gasket leaks or cylinder head cracks?

Boise, ID

#8 Oct 11, 2010
It's not easy. I would start with compression check (get a cheap gauge from harborfreight and follow instructions). Open up a radiator when engine is cold, start the engine and see if any bubbles. Watch for white smoke in tailpipe.

Blown head gasket, or crack between cylinders you will detect with compression gauge. In my case, compression was good, but I had bubbles in coolant and intermittent white smoke. I though it is intake manifold gasket. There are 4 coolant passages to the intake manifold, 2 at the front, and 2 at the back (capped off). Sometimes it starts to leak and you'd get misfire in 3 and 4 cylinder.

I took off maifold and the gasket was OK. I decided to take it further and took off heads. At first I didn't see cracks, but the guy at the machine shop put some pressure into coolant passages and I saw cracks right between the valves. These cracks are hard to see unless you know what to look for. And they don't leak coolant all the time, only when you put load on engine or the engine is cold. Then it may spray coolant on hot spark plug and kill it.

I would say, if you have enough symptoms to warrant tearing down the top end, you just go for it and deal with whatever you see. Taking off intake manifold is easy, and if you see bad gasket - just fix it, and see what happens. If not, then go for heads. The bottom end of this engine is really strong and was in excellent shape, with most original honing and pistons in pristine condition, despite mileage. To me it seems worth it to put some work into fixing the top end and get some 300K-500K miles out of the bottom end. You can get NEW heads for 140$ with all vavles and seats, shipping included!

Killeen, TX

#9 Apr 6, 2011
Replace the Idle Control valve. It governs the idle, runs off vacume from the engine and has only two bolts and an electrical conection. Sits on the top right side. Costs about $60 and takes less than 5 min. to replace. Don't even have to get your hands dirty.

Coxsackie, NY

#10 Apr 6, 2011
Still having the problem. I suspect it may be a crack in the head as I do need to refill the coolant every few months but, I've already managed to make it to 150,000 and she runs the same as it did at 35,000 so I've gotten used to it. I keep that it mind if ever the need to tear the top off comes up and I will let y'all know if the problem goes away.
Thanks for the info.

Mankato, MN

#11 Jul 8, 2011
Its the spark plugs turning out that cause this problem in my 2000 Ford Ranger four liter. When it starts to miss when starting or jerks excellerating, I check the plugs and always find one that is screwing itself out. Clean the threads and screw it back in and problem solved.

Salt Lake City, UT

#12 Mar 3, 2012
I'm having the same issue with my 2000 ranger. I've replaced everything it seems from the coil, plugs, wires, upper intake manifold gasket(s), O2 sensors (up and down stream), master airflow sensors, and temp gage. I use NGK iridium ix plugs now. My #4 cylinder always goes out after 3-4 months, and I'm not giving up. I have the manual that tells you how to fix issues. I'm pretty much done with paying for mechanics that suck at troubleshooting… which is ironic, cause that's all they do. I'll try for checking for cracks… that makes a lot of sense. Thanks for the posts!

South Africa

#13 May 16, 2012
No 5 rocker keeps on breaking no matter what I try

South Africa

#14 May 16, 2012
I have sent both heads in for checking including the cams,swopped rockers around but find when you start up all goes well up to an hour or pushing it 1 day and I get the same problem arising with the no 5 rocker breaking please help before I pull out my hair and not to mention time and costs

Lincoln Park, NJ

#15 Jun 17, 2012
what is the most likely/common problem for a slight miss fire? ranger 4.0 v6. plugs, wires and injectors cleaned, along with fuel and air filter

Elkins, WV

#16 Sep 6, 2012
I have a 2000 Ranger XLT with 215K and am having to change the plugs every 3 months or so. It is usually 3 months when it starts missing. I was told that is has a head gasket leak, but it has never over heated and I never have to add coolant. I cannot detect any signs of a head gasket leak. Any suggestions?

Newark, NJ

#17 Mar 5, 2013
Hi I have a 2000 range 3.0 when the motor is cold and u start it it's hard to start the cel came on and it's saying I have a misfire in cylinder 1 3 and 6 there are new heads on it along with plugs , wires, coil pack I don't know when else to check

Washington, NC

#18 Mar 18, 2013
i have a 2000 ranger 4.0 it has rough idle and surges until it warms up and losing a little water out tail pipe. i was wondering what could be the cause of this???

Roseville, CA

#19 Jul 9, 2013
I have a 2000 Ranger 4.0 it's fouling a plug every couple of months I change the plug and it's back to normal, could a different heat range be the answer for this problem or maybe Platinum plugs
I'm using Ford Motorcraft
SP-500 AGSF22FM ??

The Colony, TX

#20 Jul 15, 2013
i have a 2000 ford ranger with the 4.0 OHV engine as well. have 305k+ miles on it and haven't replaced anything. before i do an entire engine rebuild because it now miss fires on the 4th cylinder and the plug continues to go bad what do yall suggest i do? id rather not do a full rebuild because lets be honest. i dont have the money for it. what are yall thinking? new heads?(starts rough but smooths out after a few seconds as well.)

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