2.5L ('98-'01) P0442 rough idle and stalling. Everything checks out.

[ben_2_go]

See if you can get a timing light, like $5 at a garage sale or maybe a friend has one, lol
I would check the timing on #1 on both coil packs, warm idle should be about 20deg BTDC

No pinging with only 1 coil pack in use would point me at PCM issue in a 1995 and up 2.3l/2.5l lima
Not definitive but certainly could be the issue

OK. I'll try that. I may try another set of spark plugs and wires. Possibly another set of coils.

 

[ben_2_go]

See if you can get a timing light, like $5 at a garage sale or maybe a friend has one, lol
I would check the timing on #1 on both coil packs, warm idle should be about 20deg BTDC

No pinging with only 1 coil pack in use would point me at PCM issue in a 1995 and up 2.3l/2.5l lima
Not definitive but certainly could be the issue

I put a timing light on it today. The rpm were jumping around between 900-1000. The light showed the timing to jump around with the idle as expect, but both coil packs registered the same. Right around 10 degrees of timing. I feel like I've gotten more bad parts. I keep getting bad parts across all of my vehicles. I quit working on my others and have been concentrating on the Ranger because of that. I can't afford to buy parts two, three, or four times across seven vehicles. It looks like everything is pointing at coils, spark plugs, and spark plug wires again. I have less than 200 miles on these parts and a lot of other parts.

 

[Blmpkn]

I put a timing light on it today. The rpm were jumping around between 900-1000. The light showed the timing to jump around with the idle as expect, but both coil packs registered the same. Right around 10 degrees of timing. I feel like I've gotten more bad parts. I keep getting bad parts across all of my vehicles. I quit working on my others and have been concentrating on the Ranger because of that. I can't afford to buy parts two, three, or four times across seven vehicles. It looks like everything is pointing at coils, spark plugs, and spark plug wires again. I have less than 200 miles on these parts and a lot of other parts.

Are all the ignition components Motorcraft? Ford's are fussy and really want OEM ignition bits.

 

[ben_2_go]

Are all the ignition components Motorcraft? Ford's are fussy and really want OEM ignition bits.

Yes except the spark plugs. They are Denso TT platinum which should be as good as, or better than, the OE Motorcraft plugs.

 

[ben_2_go]

@Ron D my catalytic converter is partially clogged. Could this be part of my spark knock issue? When I check the back pressure at the forward 02 sensor location, it bounces between 1.5 and 1.7 PSI. When I was a tech, we suggested a new cat at anything 2 psi and over. I haven't had the chance to change out my spark plugs. I think they maybe a problem. I used a friends spark plug wire tach to check each spark plug wire and all were getting consistent spark. We even used a spark checker. The spark was thick bright blue arch on all plug wires. Refueled with 93 octane and added Techron to the fuel. That helped, but I still get spark knock on the slightest hill.

 

[Kitcat]

I just redid my DPFE sensor and wiring along with EGR valve and tubes. It was running great with no issues at all and no codes. Coming home from dinner a few nights ago, it stalled while sitting at a red light. Restarted, but had to keep my foot on the throttle or it would die. By the time I got home, it was idling but erratic. Scanned the PCM and got code P0442. I know this is usually a fuel cap issue but that wouldn't cause running problems. The IAC vlave isn't very old. That could be the issue. The purge valve and charcoal canster valves have never been changed. I hate to throw parts at it, but I may change all three parts because their age, and the IAC valve was a cheapo Chinisum part. Anyone have any other ideas before I start buying parts?

don't really know for sure but sound like something mine did the stalling thing but mine wasn't throwing any codes but check a small vacuum line that you can only see the nipple its supposed to be on if you look though the wheel well over the passages front tire and see if it came off that was the problem with mine

 

[Kitcat]

I just redid my DPFE sensor and wiring along with EGR valve and tubes. It was running great with no issues at all and no codes. Coming home from dinner a few nights ago, it stalled while sitting at a red light. Restarted, but had to keep my foot on the throttle or it would die. By the time I got home, it was idling but erratic. Scanned the PCM and got code P0442. I know this is usually a fuel cap issue but that wouldn't cause running problems. The IAC vlave isn't very old. That could be the issue. The purge valve and charcoal canster valves have never been changed. I hate to throw parts at it, but I may change all three parts because their age, and the IAC valve was a cheapo Chinisum part. Anyone have any other ideas before I start buying parts?

check that vacuum line. i changed a shit ton of parts including plugs wires coil packs throttle positioning sensor crank sensor cam sensor air idle control sensor and the list goes on. just to find out it was that vacuum hose

 

[ben_2_go]

@Kitcat I've changed most of the vacuum lines and fittings. The smoke test would have revealed any vacuum leaks. I also sprayed ether on all the vacuum fittings and areas where vacuum lines are attached, even the black vacuum accumulator ball, and nothing changed. My only issue now is a slightly unstable idle and really bad spark knock like I have bad fuel or low octane fuel, which I do not. I'm on my 3rd tank of 93 octane, and I have been through the ignition system again.

 

[Blmpkn]

Putting 93 into something that's knocking is a terrible bandaid.

The higher the octane, the slower the burn. Slow burn on something that only needs 87 means an incomplete burn, which leads to an increased amount of carbon buildup.. and carbon buildup if its bad enough will itself cause pre-ignition

 

[boss3.0lranger]

Not sure year n engine size.
Since dpfe n egr then engine unstable.
Not all egr's are same there is different orface size to feed gas into intake
2 unplug egr and feel if vacuum is being feed to valve? Should not at idle
3 egr to mounting leakage of vacuum or allowing gas by egr.
4 unplug ALL lines to intake see if idle is stable.
Unplug dpfe retest do not need at idle
I do recommend scanner that read pod values
PCM monitors feedback but if inputs are wrong get wrong adjustments.
If connector to dpfe was change make sure wires are correct, old connector color wires same as the one you installed
Disconnected battery will reset idle strategy and reset iac 10min approx.
Key on engine running test n codes

 

[boss3.0lranger]

"Scanner to read PCM pid values "

 

[boss3.0lranger]

Unplug maf sensor retest ping, baro pid not match your area. Test low fuel pressure.

 

[ben_2_go]

Please read all of the comments. I have been through all of this multiple times.

 

[ben_2_go]

Putting 93 into something that's knocking is a terrible bandaid.

The higher the octane, the slower the burn. Slow burn on something that only needs 87 means an incomplete burn, which leads to an increased amount of carbon buildup.. and carbon buildup if its bad enough will itself cause pre-ignition

Octane rating - Wikipedia

en.wikipedia.org

 

[boss3.0lranger]

Plug cat would cause hard start and bog idle fine or low then wot bog
Spark knock mechanical timing
Carbon
Ing timing
Low egr flow
Low fuel psi
Injectors plugged
Lean mixture from vacuum leaks

For me I would rule out all external sources,
Sensors can be influenced PCM calibration say intake air temp shows to cold or cooling system temp ect
All will cause PCM timing to advance.
Ford design dual coil pack to aid in combination flame travel.
Spark knock is pre-ignition unwanted combustion.
Maf with baro hz
Low fuel pressure