93 3.0 erratic miss at idle and while driving, acts like it momentarily shuts off / Could the distributor ignition pickup, be the problem?

[red ranger danger 93]

Hello to anyone who could help me.

This problem all started with the truck not wanting to start. I had no spark, but I could hear the fuel pump start up at key on engine off (koeo). I then started changing/chasing parts.
I put in new plugs, new wires, new distributor cap and rotor, coil, ICM. I finally got it to start after the ICM was installed. I thought this was the problem, but then I had the mystery "miss" start happening. So then, I started buying more parts, such as the IAC replaced, mass airflow sensor, throttle position sensor, and the PCV, both temperature sensors were also changed.

I thought most of these parts would be just a good tune up anyway. Some of these parts had never been replaced, with 300,000 + miles on my truck. The oxygen censors had been changed a few years ago. After all this, the "miss" was occasional, but now it is more consistent and worse. The truck is a manual, if that means anything.

Thanks in advance to anyone who has any information or advice they are willing to share with me.

 

[19Walt93]

Is the ignition module a Motorcraft part? Are the plugs and wires Motorcraft? The magnetic pickup is called a stator and is less likely than the module to do that.

 

[red ranger danger 93]

plugs, yes, icm, no, wires, no, not the cheapest, but not m.c. i didn't know where to start, so i pushed the buggy in and loaded up, not knowing, what it could be.

 

[red ranger danger 93]

i forgot new fuel filter also.

 

[rumblecloud]

Kind of late to the party to ask, but have you tried pulling codes at all?

 

[red ranger danger 93]

yes, i did with obd 1 code reader, 536,538 i can't remember for sure but i think they were about the temp. what do you think about the generic icm, could be the problem! it started this soon after putting it on, but without the new icm, it wouldn't even start. hard to think it would fail days later.

 

[bobbywalter]

Icm....ghost fail. Even motocraft.


At 300k...do a hot and cold compression test and a leak down.

And again...read the plugs and buy a vacuum gauge before baskets of stuff you don't need yet.

 

[red ranger danger 93]

i should have mentioned this is the second engine, pro rebuild/replace, that's got a leaking rear main, some head gasket leaking as well. real pro's right. the out of business company, gone. wiped my butt with lifetime warranty papers. technical skills list is very short, and that time thing. over the road gone to long trucker. with every part came hope, it said it on the packaging. i have had the truck 25 of the 29 years, the body is in great shape, the rest of parts ,i"e" drivetrain pretty wore out. new prices crazy, crossroads, right.

 

[red ranger danger 93]

The auto parts store said they would replace the generic ICM, so I got another one and installed it. There was no difference in the engine after installation at idle. It would sometimes miss at 15 seconds, sometimes at 30 seconds, sometimes as long as 1 minute before it would miss, and then sometimes it would "miss" twice in a row. What I mean is, when it is idling at about 800 rpms to almost a stall, and then instantly right back up to 800 rpms.
No real pattern to the "missing". I took it out for a test drive and after accelerating in each gear up to 2,800 rpm to 3,000 rpm it would start "missing" until I backed off the throttle or shifted to a higher gear. I drove home and sat in the drive-way and held the throttle to 3,000 rpms for more than 3 minutes and it never missed once?????

The code reader showed a 536 and 538 code. After mentioning the head gasket leaks, I took a closer look, and the oil actually appears to be coming from under the valve covers on both sides, with more on the left (driver's side), or maybe it is not head gasket leaks, or it could be both???

Thanks again for all the advice.

 

[bobbywalter]

My exhaust flange area is cracked and the valve cover rail and leaking oil into the exhaust and down the back.


It's gonna get some JB weld instead of a better engine due to new projects .


I am leaning...you need a 5.3.

 

[red ranger danger 93]

You are probably right.... thanks

 

[mc17eln]

Rent the cylinder compression test tool from your auto-part store. '98 and newer models have a fuel shut-off switch in the passenger foot well. If yours doesn't have one, cut power to the fuel pump. Then do the compression test.

Straight from the Ford Workshop Manual:

Compression Test — Test Results
The indicated compression pressures are considered within specification if the lowest reading cylinder is at least 75 percent of the highest reading.

If one or more cylinders read low, squirt approximately one tablespoon of engine oil on top of the pistons in the low-reading cylinders. Repeat the compression pressure check on these cylinders.

Compression Test — Interpreting Compression Readings

1. If compression improves considerably, piston rings are faulty.

1. If compression does not improve, valves are sticking or seating incorrectly.

1. If 2 adjacent cylinders indicate low compression pressures and squirting oil on each piston does not increase compression, the head gasket may be leaking between cylinders. Engine oil or coolant in cylinders could result from this condition.
   Use the Compression Pressure Limit Chart when checking cylinder compression so that the lowest reading is within 75 percent of the highest reading.

 

[red ranger danger 93]

Hello mc17eln,

Thanks so much for that helpful information, I will definitely look into that.

 

[red ranger danger 93]

I believe that I have solved my truck problems:

Hello to everyone who has helped me, or who has read my previous posts/threads, and may be experiencing an erratic miss. I believe that I have solved my problem., but with the answer being one or both of these things, that may have happened at the same time, or may have been failing at the same time. I finally changed the distributor so that I could change the "stator" (what I called the magnetic pick-up). After getting the timing set the truck was running great again. Later on in the evening, I went for a short drive and the battery light came on, I did a test and it showed that the alternator had failed. I am not for sure if this was the whole problem, or only part of the problem, from the beginning when the truck would not start I had only test drove it a few miles after finally getting it started. Hindsight being 20/20, and with a new battery in the truck before all this started, I did not question that the alternator could have been part of the problem, but the stator definitely was.

Thanks for all your help, and hopefully this information will help someone else.