1994 Ford Ranger very bad idle problem

[skullz696969]

I have a 1994 Ford Ranger 2.3l 5spd it started idling very badly a couple of weeks ago but for 6 or more months it has been squeaking very obnoxiously but only when it is cold out. I have heard that it could be the crank sensor causing the squeaking and newly starting rough idle. Anybody else have any input. Thanks for the help ahead of time.

 

[chilsam]

Crank sensor

I don't think the CS can cause a squeak,sounds like a bearing "ac,waterpump,alt" or belt to me.The rough idle could mean time for a tune up.

 

[skullz696969]

I just changed the oil 500 miles ago, New plugs and wires with spark gap of .44 as of 30 miles ago. I have gotten it scanned and it came up saying my MAF was bad but i knew that and i did the temporary test to see if unhooking it fixed it and it did nothing. When they scanned it it also came up with low compression on cylinder 4. Could the low compression cause the intermittent rough idle. When it is cold it runs fine but within 5 minutes it idles like crap and goes to die down then the throttle will pick up and it will be fine.

 

[skullz696969]

So just got compression numbers
Keep in mind computer says cylinder 4 is low.
Cylinder 1 60psi
Cylinder 2 115psi
Cylinder 3 110psi
Cylinder 4 115psi
So i was thinking what is the likely hood that the valves are sticking?
Or what other problems could cause this cause its not leaking oil nor burning it.
Any body else have this problem or currently having this problem?
Thanks

 

[fastpakr]

What -exactly- did the computer say? If you're unsure, scan it yourself. All you need is a paperclip. Instructions are on the main TRS page.

 

[skullz696969]

Ok thanks ill go check it my self now. Will post results soon.
Thanks

 

[chilsam]

Burnt valve?

So just got compression numbers
Keep in mind computer says cylinder 4 is low.
Cylinder 1 60psi
Cylinder 2 115psi
Cylinder 3 110psi
Cylinder 4 115psi
So i was thinking what is the likely hood that the valves are sticking?
Or what other problems could cause this cause its not leaking oil nor burning it.
Any body else have this problem or currently having this problem?
Thanks

or maybe a blown head gasket or bad cam lobe?

 

[skullz696969]

Yea im leaning more and more on the head gasket.
Im gonna sit down and think about getting it replaced or just waiting till the motor dies and then find a turbo tbird motor. Such a tough decision.

 

[chilsam]

Bubbles

Are there bubbles in the coolent or strong exhaust odor when you take off the cap? If so then it is a gasket.

 

[skullz696969]

Thats the funny thing there is no bubbles in the coolant or strong odor thats the first thing i checked and no to both which puzzles me.
I have absolutely no idea why it idles crappy and wants to stall. It drives perfectly fine.
Idk if the crankshaft position sensor would cause the bad idle or not.
Im out of ideas.

 

[chilsam]

IAC valve

Could this be sticking?

 

[skullz696969]

That was my original thought and i had replaced it and its still doing it. I traced the wires and checked for resistance and they were fine.
This morning i started it and was standing in front of it and all of a sudden the RPMs would drop to probably around 300-400 and then it would rev its self up to around 2500 rpm and then drop back down to 300 - 400 it did this for like 7 to 8 times then i shut it off.
It will drive fine it just idles terribly.

 

[fastpakr]

Leakdown test.

 

[93 4x4]

Just my thoughts, I had the same symptoms and it tuned out to be the brain,check came up map sensor and had random codes,bad idle. diodes on the brain were leaking on the board and causing the problems. check the brain for black circles under the diodes on the board. but I didn't have low compression readings

 

[chilsam]

coolent temp sensor

That was my original thought and i had replaced it and its still doing it. I traced the wires and checked for resistance and they were fine.
This morning i started it and was standing in front of it and all of a sudden the RPMs would drop to probably around 300-400 and then it would rev its self up to around 2500 rpm and then drop back down to 300 - 400 it did this for like 7 to 8 times then i shut it off.
It will drive fine it just idles terribly.

The one in the intake that sends info to comp might be bad