I have a 2000 ranger 4x4 with the 3.0 engine and automatic trans.
I had auto zone test for codes and there are none present.
I changed the Spark plugs and wires but this didn't help (Much). A few days later I noticed the coolant level was way low.(more than half a gallon)
When It started missing I was doing about 35 in a 35 mph zone and noticed a lil fluttering sound and a slight loss of power it seemed. Now if you get the truck up to about 43 to 45 MPH and hold speed steady the engine will go into a Violent Shake. You have to let off of it till you get back to about 40 MPH to make it quit the Violent shaking.
I suspect a cracked head due to coolant lose and no visable signs under the truck or engine.and no codes.I DO NOT find any signs of antifreeze on the dipstick though.
I bought a cheap compression tester from Harbor freight a while ago and I read a post that had a link for compression testing. Now I can't find that .
Does anyone know that link?
Thanks Guys
ZZ

 

wish i could help

 

Any Haynes or Chilton manual will give you instructions for compression testing. Never performed the test myself (never needed to), but here's a paraphrase-ment :

*gets coffee*

1.) Clean the area around the sparkplug holes to prevent debris from entering the engine cylinders.
2.) Remove all of the spark plugs from the engine (for your V6 engine).
3.) Block your engine throttle all the way open.
4.) Disable your ignition.
5.) Disable your fuel pump.
6.) Attach the compression guage to the #1 spark plug hole.
7.) Have somebody crank the engine for at least 7 compression strokes and keep your attention on the gauge. Compression should build up quickly. Low compression on the first stroke followed by gradually increasing pressure on successive strokes indicates worn piston rings. A low compression reading on the first stroke which doesn't build up during successive strokes indicates leaking valves or a blown head gasket/cracked head. Deposits on undersides of valves can also lead to a low compression level. Record the highest reading obtained on the gauge.
8.) Repeat the above steps for the rest of the cylinders and compare to your engines specifications (I wrote them in below).
9.) Add about three squirts of engine oil into each cylinder.
10.) Repeat your tests, and if the pressure increases after the addition of the oil, the piston rings are definitely worn. If the pressure doesn't increase significantly, then the leakage is most likely occurring at the valves or head gasket.
11.) If two adjacent cylinders have equally low compression, there's a strong possibility that the head gasket between them is blown.The appearance of coolant in the combustion chambers or crankcase would verify this condition (incidentally, I believe there is a tool to test for the appearance of combustion by-products in the coolant).
12.) If a cylinder has a reading about 20% lower than the others, and the engine has a rough idle, a worn exhaust lobe on the camshaft could be the cause.
13.) If the compression is unusually high, the combustion chambers are probably coated with carbon deposits.
14.) If compression is way down or varies wildly between cylinders, you should probably take it to a shop for proper testing.

**Note, you should check these figures by getting a copy of the shop manual for your vehicle, which will also give you clearer instructions.**

Compression: lowest reading cylinder must be within 15 PSI of highest reading cylinder, with a 100 PSI minimum.




Hope that helps a little, and good luck!

 

Thank You sir I'm sure it will be helpful.
ZZ

 

Well I still got the problem of the truck shaking violently at 43 to 45 MPH
I started to do compression test and the plug that goes in the spark plug hole doesnt seem like the right thread. I do not want to cross thread this in the spark plug thread hole So I took to a shop today, but the shop was closed.
While looking around I noticed antifreeze dripping on the skid-plate under the truck.
Tracked the leak down and think maybe it was coming from pressure cap.
I put a new one on and took it out to the highway and tan the heck out of it. Ran great and set the cruise control at 70 and it just purred. When I slowed back down coming into town I noticed it ran a rea; smooth till I got back to 43 to 45 it still shook till I pushed the overdrive switch (raised the RPM's) and it ran smoother.
I'm beginning to wonder if this is a transmission problem instead of an engine problem.
I now don't see any signs of an antifreeze leak.
Anyone have a similar problem or know what this might be cause from?
Thanks for any help.
ZZ

 

Try turning the overdrive off?

 

WHen I start the truck and take off is when it shakes at 43 to 44. I push the switch in (Over drive off Light on dash on) it smooths out some.
It is still a little rough till I let off of it and try to maintain constant speed.
Hope this makes my problem a little clearer.
Thanks

 

UPDATE: It finally got warm and nice enough today to work on my truck.
While it was running I pulled each plug wire off the coil one at a time, and #2 made no difference on or off but was getting good spark.
I put a new injector and it cured my problem.
Just thought I'd let others know since this problem about ate my lunch for me.
ZZ