Gambled on a 97 2wd 2.3 5spd for a winter beater. Truck had a miss when I bought it but hoped it was something simple. Symptoms are cylinder #1 misfire and evap purge code. Noticeable miss through exhaust. If I start it cold and let it sit it idles ok even with the steady misfire. But if I rev it up it it seems to chug a bit and when it comes back down it idles real rough and sometimes stalls. Infrared temp gun measures #1 exhaust primary much cooler than others at idle and above.
Things i've tried so far.
new autolite platinum plugs and good wires
*new motorcraft injector on #1
cleaned maf sensor
checked and rechecked for vacuum leaks by spraying with brake cleaner.
plugged off pcv, evap purge and booster. no change.
coil packs
cleaned iac solenoid
applied vacuum to egr diaphragm to make sure valve was not stuck
*Took truck in to shop for a diagnosis and he said the spark checked out good and even put the scope on it. Guy was convinced it was the #1 injector. He did a cold cranking compression test and said everything was good. He couldn't find andy vacuum leaks either. He said the sensors checked out.
I was a bit more thorough with my compression testing. Cold cranking I got 140psi on 1&4 and 150psi 2&3. Running at idle #1 was 70 and #2 was 90. I didn't check the others. While running I "snapped" the throttle and got 125 on #1 and 150 on #2. Didn't check others. It looks like theres something going on in the valve train for #1. But that doesn't explain how the idle changes/stalls when I rev the engine. My thinking is if the problem was isolated to #1 why would it affect the engine so much? Could it be the ecm trying to adjust fuel trims? The exhaust smells terrible at idle. Smells like the cat is loading up. I do have a basic scanner which allows me to see live data. But not sure what Im looking at most of the time. Any help will be appreciated!!

 

You've been busy on this puppy & good idea to have posted up the numbers attained so far. Might be helpful if you'd also post up All pending, or set trouble code Numbers, as they can often provide good trouble shooting clues.

When it's missing, are their any unusual mechanical sounds around #1 cyl on the top end & how does the #1 fuel injector sound when listened to with your stethoscope, compared to the others? If it's different, is the sound in time with the miss?

If your scan tool is the ELM type, try loading FORScan on the viewing device of your choice & have it take an in depth look at all of the computer/controllers & sensors PID's to see if it can spot something amiss, or borderline, if no good trouble code clues are found.

I suppose it could be a CCDI = Combustion Chamber Deposit Interference problem, if #1 cyl has been acting out for some time.
Maybe even a clogged cat converter causing back pressure problems that are confusing things, if the misfire condition has been around for a while, as the cat has to process all that unburned fuel, so can over heat & melt down internally, causing excessive back pressure.

Hook up your vacuum gauge & scroll down to review the various test scenarios here for clues. How to Use and Interpret a Vacuum Gauge

I'd also perform a fuel pressure & flow/volume over time test & post the Numbers.

More thoughts for consideration, let us know what more you find.

 

Don't want to say it out loud, but I would be checking two things: cam lobe condition on #1, and valve seat condition. If the lobe is flattened(last cam lobe to get lubed, oils from the back) it won't lift the valve and allow flow as well, perhaps idling OK, but falling on its face at more rpms. Some Fords, more Vulcans, I think, have seat problems where the valve recesses into the cylinder head and causes misfire. The misfire remains above idle, but you cannot detect it w/o instruments most of us don't have.
I'd take off the cam cover, and visually check the lobes, comparing lift. If the lobes were equal to #2,3,4, I'd pull the head.
An alternative, if you have one, is a bore scope that would let you insert a camera probe through the spark plug hole. I'd then inspect the valves, lift, and seats as much as possible.
Off the top of my head, a limited flow from a flattened lobe would produce similar results as an injector that was not working quite right. Less fuel than normal is 'sort of ' similar to less fuel-air mix... I'd think.
tom

 

I could not get any work done on truck til recently. I removed the valve cover and inspected the valve train. Everything is intact and no signs of failure or excessive wear. Also, had the idea to remove the o2 sensor and run it briefly in an attempt to eliminate the possibility of a plugged cat. Still missed and wanted to stall after snapping throttle. Still need to check fuel pressure yet. I did add a mechanical oil pressure gauge for the hell of it and get 60 cold and 40 hot all at idle.
While moving the truck into the garage it stalled after I revved it up pretty good (got a lil frustrated). I immediately went to restart and the sound it made was not normal. It sounded exactly like it did while cranking with the plugs out for the compression tests. I waited about ten seconds and tried again and it cranked and started normal. I had noticed something was off the last coupe times it stalled when I attempted to drive into town. In my frenzy to get it restarted I don't pay much attention to it at the time.
I'm usually pretty good with fixing vehicles but this has really got me puzzled. Not sure where to look next. Luckily haven't needed the truck yet as I use a company truck for work.

 

Have you performed any of the suggested preliminary diagnostic vacuum gauge tests, compression test, or scanned for trouble codes? If so, post up the results as they can quickly help focus a trouble shoot.

 

Years Back (like 1997) I worked on a 79 Mustang 2.3Lthat a guy got from a Junk Yard (whole car for $350). Calls me one day says it will barely run. Get it bad cam lobe, and one follower was popped out. Put a cam in out of a Cracked head as well as lifter and follower. Car ran decent until the owner lost it to the police impound.

 

Had a chance to play with it again today. Started it an let it idle with a vacuum gauge. Getting somewhere between 15-20 with a steady needle and the misfire. Revved it up a few times to maybe 3k and when throttle blades snapped shut the vacuum was still around 20ish. Of course after revving it began to idle very poorly as it usually does. At this point vacuum was maybe 10 or less. The needle was fluttering slightly. My vacuum gauge is not very accurate as it does not return to zero at rest. It reads about +5 and I've added this to the actual gauge readings to come up with the final results. I checked the timing belt today also. The belt looks fine and the marks are lined up. I pulled #1 spark plug to verify tdc.

I played around with my scan tool for a while watching the live data. The short fuel trim was all over the place going anywhere from four to twenty. The o2 sensor was anywhere from .090 to .530. When i first brought this home the stored codes where P0443, P0301 and P0171. It also had a pending P0304. At that point the truck had the miss but was still drivable. They've all since been cleared and reset. Today the P0443 came back. Plugging off the vacuum line from the purge solenoid doesn't change anything. My compression test results are in my original post. Thanks!!

 

So you have a Generic code for the Fuel Evaporator system. Plugging off and keeping Vacuum from that system is not a proper repair or diagnostic. Plugging off vacuum can cause a trouble code.

If it was me I would:
1. Change my fuel filter(s).
2. Check my fuel pressure at idle.
3. Pull off the throttle body Clean & inspect it.
4. Check out my fuel rail & lines going back to the tank.
5. Make sure the O-rings on the replaced injector are good.
6. Pull the Cam cover and make sure the Cam, Followers, Lifters, and Valves are operating properly.
7. make sure the ignition system is working right.

 

Fuel filter was replaced by the previous owner. Once I can buy or barrow the appropriate fuel pressure tester I will test the fuel pressures. After that I can dive into troubleshooting the fuel system as needed. If the fuel pressures were indeed low, how could this present a rich burn condition? Removing the cam cover revealed no useful information. Although I was very impressed with the felpro valve cover gasket that came with the kit. Its blue silicone with anti crush sleeves in the bolt holes and was molded in such a way that it wouldn't squeeze out while torquing it down. Ignition system appears to be functioning properly. There are new plugs and wires and the shop that misdiagnosed the fuel injector used an ignition scope to confirm operation. The o rings on the new injector are good. There was no improvement at all after installing the injector. And I should say that it was not worse either.
With the purge solenoid, my thinking was to remove the vacuum line and plug it off to see if there was any improvement. What I failed to mention was once I figured it made no difference, I did reconnect the line. Maybe I'm thinking about this evap code wrong. I assumed it meant the purge solenoid was open when it was not supposed to be. I have a hard time believing the source of the evap code can cause such a terrible drivability problem. My '97 f250 summer truck pops the same code occasionally with no effect on drivability at all.
The plugs do look sooty and the exhaust smell is very rich. The ecm looks like its trying to compensate for a lean condition that I can't prove even exists. I've been all over this engine looking for vacuum leaks and even removed each line individually from the intake and plugged them off while running. Could this be as simple as replacing the o2 sensor?

 

if the o2 sensor gives a lean signal the ECM does enrich the fuel mixture.
But what is the cause of the lean read? If a Sensor is not faulty and you change it, you will have the same condition, just with a new part telling you the same thing.

Find someone who has a Ford 97 Ranger shop book. Find the test and diagnostics for systems you need. Do the tests, find the error. Do not get over dependant of OBD-II scan tools. Live data does not always give anything usefull.

One one my GM cars I recently has a random miss-fire. would come and go when at operating temps for 20-30 minutes. Nothing showed on my Auto-link or my Buddies Snap-on scanner. I had a dang good idea what it could be, went to a shelf in my garage. Grabbed a used Coil/Module/Mount Bracket assembly, swapped that and a damaged plug wire. Module for the coil was going bad, getting heat soaked and causing a random cylinder miss. Also found #5 on the V6 has a bad coil tower. Yet no scan tool showing data streams showed that.

I used live data to show on my 96 5.0L Explorer that my 02 sensors work, it just anytime I goose it or turn off over-drive (automatic transmission) the exhaust flow moves so fast the 02 sensors read 0.00 until the flow returns to that of 10-40% throttle. To replace the exhaust & cats is more then the truck is worth, I just live with the Mustang GT sounds and the SES light on.

A lot of repair shops have Parts Changers not actual mechanics that can diagnose a system.

As for a Fuel pressure tester:
Some compression testers can switch hoses and do fuel pressure testing. Also some auto-parts stores 'loan' them (buy it, money back upon return).

 

Checked the fuel pressure. Looks good at 30-35 idle. Fuel pressure does not change when it runs like crap. Used lived data and short fuel trims to confirm lean condition. At idle its 20+ish and at 2500 its 10 or less. Several places online say that this would confirm a lean condition. So then I unplugged the o2 sensor to force open loop and revved it up. Same problem, runs like *** and chugs/stalls. BUT since the ecm is not fueling to compensate, the exhaust smells somewhat normal but obviously lean/hot. I AGAIN checked for vacuum leaks by disconnecting the small lines from the manifold and clamping off the booster and pcv lines. No change. Sprayed manifold gasket flanges and Intake piping. Sprayed Injector bases. I also checked the egr tube temps to see if it were open. Pipe is cold and no egr codes. I had previously checked the diaphragm by applying vacuum at idle and it immediately opens and closes when vacuum is removed.
What confuses me is how can the problem be rpm dependent? Yeah it has a miss at idle. But until rpms exceed say 2500 it runs ok. After revving it up it starts running very choppy and won't idle for ****. If I really give'er and rev up 3000-4000 its even worse. And will most likely stall when returning to idle. So I figure theres likely two different problems here. The miss, and the more severe rough running stall problem. Remember, I bought the truck with the miss and test drove it for several miles without issue.
So the last thing I did today was bypass the iac completely. I inserted a piece of thin cardboard between the gasket and housing blocking off the ports. The engine will continue to idle, but its very low and rough. Revved the engine and same problem came back. Pretty sure its not supposed to idle at all. Then thought about the throttle blade minimum position. Doesn't look like anybody messed with it and for sure nobody messed with it after I bought it. Now what?

 

The measured fuel pressure seems off to me. The fuel filter replaced by the previous owner may or may not be actually replaced. Is it the correct filter? Is it installed pointing the correct direction? Does the fuel pressure bump when you remove the vacuum line from the fuel pressure regulator? Have you take a whiff of the vacuum line to check for a punctured/ruptured diaphragm, which would allow fuel to get sucked into the intake?
Revving the engine, and then it running like dog doo indicates something. Exactly what I can't say from here. It may be fuel restriction or lack of flow, where the system can deliver enough to run OK at idle, but not enough to run at higher rpms.
Do you still have a dead miss(miss all the time) at idle? Throw away your vacuum gauge and get one that works. Adding this to that to come up with a reading is likely measuring with a micrometer, marking with chalk and cutting with a chainsaw. Accurate. Not.
Do you have a distributor or the coil pack with 2 coils & 4 wires or what? Have you swapped plugs?
tom