1996 Ford Ranger 4.0 V6 have codes P0306 and P0174 need some advice please

I will rent the noids and check with plug 6 wire off at idle and above 2000 rpm to check it. Monday. Thanks

I checked the compression spec The lowest cylinder must be 75 percent of the highest. Cyl 6 is 86 percent of cyl 4, within spec. Thanks

I had a question on using the NOID lights. Should I test it cranking only and then running? To crank without starting I removed coil pack fuse No 19. Should I check it while cranking? And then while running?

Also does it make a difference when testing compression on a cold engine vs a hot engine? I would rather check it cold so I don't get burned.

Also I am uncertain how to secure spark plug boots on the plugs.I want to make it click once it engages the top of the plug securely but with these Bosch wires I can't get an affirmative click. What I do is pull gently back and forth to see if it's on the nub spot. Can you give me an idea how to get a good click when installing? I have strong hands but of the six wires I installed not one click.

Thanks

Hi, did you mean to say the compression psi goes down with hot engines or are the compression checks supposed to be done on a hot engine?The spark plug wires clip inside do not seem to be slipping up. I will test the wires with a spare plug to check how they are supposed to click or not. Thanks

I am writing this list to do so I remember:

1 Check cyl6 injector plug with noid.
2 Check engine running at idle and 2500 rpm removing plug wire to see if misses at 2500 rpm.
3 Change oil and filter once missing is fixed.
4 Please add to my list as I get test info to you.

I hope you had a pleasant holiday, mine was great. Thanks

Last time I drove it 2-3 weeks ago codes were P0300 and sometimes P0174. I will do the noid and missing tests when it's not so cold here. Thanks

I kind of feel the noid test is unceccessary since I did it only 30 miles ago, back in June 2012. My hands get bruised and torn up. I will wear gloves from now on, either leather or nitrile. I can check whether it misses at 2500 rpm by removing the cyl 6 wire at the coil pack and see if rpm drops. Is there a better way to detect misses for sure at 2500rpm? Thanks, Pete

I forgot to ask you I sent a ten dollar donation to you through another question you answered for me, did you get it? From last week.

I found the following tip on detecting a misfire.

TECH TIP
The Paper Test
A soundly running engine should produce even and
steady exhaust at the tailpipe. You can test this with
the paper test. Hold a piece of paper or a 3 by 5
index card (even a dollar bill works) within 1 inch
(25 mm) of the tailpipe with the engine running at
idle.
The paper should blow out evenly without
“puffing.” If the paper is drawn toward the tailpipe
at times, the exhaust valves in one or more cylinders
could be burned. Other reasons why the paper might
be sucked toward the tailpipe include the following:
1. The engine could be misfiring because of a lean
condition that could occur normally when the
engine is cold.
2. Pulsing of the paper toward the tailpipe could
also be caused by a hole in the exhaust system.
If exhaust escapes through a hole in the exhaust
system, air could be drawn in during the intervals
between the exhaust puffs from the tailpipe to
the hole in the exhaust, causing the paper to be
drawn toward the tailpipe.
3. Ignition fault causing misfire.

I can prop the pedal at 2500 rpm and check it with the plug wire on and off.
Now I just have to go do it.

After reading some more in this book, I will ground the plug wire at the plug. I will use my little sparker device to allow the coil to create a normal spark while wire is dc. This is to prevent damage to the coil pack. Also I learned the way to check is for RPM drop. The miss firing cyl gives the least rpm drop when dc.

Hi saturntech9, Do you think the coil pack might be at fault? The cyl6 wire was shorting out for a long time before I started getting P0306. If I am getting spark at the no6 coil pack with a spark checker is it good or can the coil pack be a weak spark? If it sparks at all is it a good coil pack? If there's a spark problem on cyl6 should I also be getting cyl2 P0302 codes? Thanks Did you get the donation from Early January?

My main question is whether a constant shorting of the no 6 spark will damage the coil? From the images on my previous reply you can see the no6 was shorting to the ex manifold for quite a while. Thanks

I can't drive it since it's not registered. There is a bad miss at idle as though the cyl6 is not firing at all.I replaced all wires. I will check when hot and with a spare plug or my spark checker tool. Looking for blue spark right? Last codes were P0306 and P0174. I will recheck codes after I run it for a while. Thanks, Pete