'98 3.8L GL P0305 & P0174

[Beavx]

'98 3.8L GL P0305 & P0174

still battling this one. Rough idle. Misfire on cylinder 5 & Bank 2 lean.

Any suggestions, hastily replaced 02 sensors on Bank 2, imporved a little. Happens mostly when engine is warmed up. Changing fuel filter next to eliminate that cheap possibility.

Any suggestions??
Thanks in advance.

[SebringYves]

You should change your fuel filter and amybe a incector cleaning would be very helpfull.

For P0174 I have following information: Its very general but it should help you out:

P0174 DIAGNOSTIC:

1. Verify there are no other diagnostic trouble codes that could affect or contribute to setting these codes. Repair as necessary. Check for any published technical service bulletins (TSBs). Perform a visual inspection.

2. Warm the engine to normal operating temperature and use the scan tool to verify engine is in "Closed Loop". Using the scan tool, observe LTFT/STFT values. A negative value indicates that fuel is being subtracted to compensate for a rich condition. A positive value indicates that fuel is being added to compensate for a lean condition. Knowing weather the system is compensating for rich or lean condition will help in the diagnostic process. See diagram. for additional information related to fuel trim.

Typical Example:
Long term trim values exceeding +15% enrichment (Short term exceeding +20%) within a given time frame may meet the criteria for setting a trouble code for a lean condition.
Long term trim values exceeding -25% enleanment (Short term exceeding -10%) within a given time frame may meet the criteria for setting a trouble code for a rich condition.

4. Ensure oxygen (O2) sensor is functioning properly by referring to O2 sensor diagram.

Diagnosing a Lean condition:

i. Visually inspect all vacuum lines for cracks, defects, loose or disconnected lines.
ii. Test for vacuum leaks around the intake manifold, injector o-rings, throttle body, EGR system, PVC valve, plenum.
iii. Check air filter.
iv. Check for obstructions in the air duct or mass air flow (MAF) meter.
v. Check for exhaust leaks, holes, cracks, loose flanges, and gaskets.
vi. Check operation of MAP/MAF sensors.
vii. Inspect wiring to oxygen sensors paying close attention to wiring near hot exhaust pipes for damage.
viii. Verify fuel pressure is normal.
ix. Check for possible clogged, dirty or damaged fuel injectors.
x. Check for possible contaminated fuel.
xi. Check for possible leaking head gasket.
xii. Check for possible clogged EGR passages in the intake runners.
xiii. Check for proper secondary air injection operation, if equipped.

Diagnosing a Rich condition:

i. Check air filter.
ii. Check for restricted airflow to throttle body.
iii. Check idle air control device and inspect for coking (carbon build-up) or blockage.
iv. Check operation of TPS sensor.
v. Check operation of MAP/MAF sensors.
vi. Inspect fuel pressure regulator.
vii. Verify fuel pressure.
viii. Check for possible leaking and/or dripping fuel injector.
ix. Check for O2 sensor possible contamination.
x. Check for possible damaged catalytic converter.
xi. Check cooling system and coolant temperature sensor.
xii. Check for proper operation of the EGR system.
xiii.Check for possible engine misfire.

Other possibilities are: contaminated fuel, PCM grounds, O2 sensor ground, (ensure exhaust system is properly grounded). Possible PCM reprograming, check for any published TSBs for your vehicle.

[kitch]

Did you check the compression when the engine is hot with all the plugs out. My head gasket was gone between 5 and 6 with a code p0306 and bank 1 lean. It is something to check. I put a lot of cash down the shitter to get to the problem.

[wiswind]

Was there a green residue on the "upstream" oxygen sensor (that is the one that is between the catalytic converter and the engine). If there was a green stain on the oxygen sensor...then there is antifreeze getting into the cylinder.
The lower intake manifold gaskets are most often the cause of this type of leak. The head gaskets are not as high of a failure item on the post '95 3.8L engine.

I would tend to want to replace both upstream sensors together so that you have the same switching charactoristic for both banks. Oxygen sensors slow down as they age. Also....I would put ONLY Motorcraft brand of sensors in. P0174 is most often caused by a vaccum leak. I would also take a look at the spark plug for cylinder #5 and see how it compares with a spark plug from another cylinder.

Cleaning the Mass Air Flow (MAF) sensor (you should not need to replace it) and putting 2 bottles of ("treats up to 12 gallons) Chevron Techron Fuel System Cleaner into a tank of gasoline would be my next 2 steps.

To clean the MAF.....use a NON-Residue electronic cleaner......
I have a couple of pictures of where to spray......
http://community.webshots.com/album/201931518cScpNK

[Beavx]

Changed fuel filter today, no luck. But I had my uncle over who is very keen on these things. He heard an electical "snap" in time with engine revolution. I waited till dark, pulled the van in the garage, it was pitch black, and guess what? Yep. The wires for cylinder 5 & 6 were arcing out, one on the side of the engine, and the other on some wire mesh protecting some hose. Also had and occasional spark cross on wire 4. The theory is, once the computer takes over at operating temperature, it's trying to compensate for this condition, ie: P0305-cylinder 5 misfire & P0174, Bank 2 Lean. I will change the wires and plugs in the next couple of days. I will definately post the outcome.

**I am determined to not let this van whoop me--I refuse to call a mechanic!!!!!**

[wiswind]

You will want to get Motorcraft Double Platinum plugs. Other plugs will not perform as well or last as long. The plugs will be good for another 100K miles.

[Beavx]

Autozone warrantied the wire and plugs--even after their computer lost my records. Kudos on the customer service. P0305 is gone. Still have bank 2 lean, P0174. Did find a post to change PCV valve, next cheapest option. Will continue to update. Problem is intermittent now. Comes and Goes.

Thanks

[LeSabre97mint]

Originally Posted by Beavx

Autozone warrantied the wire and plugs--even after their computer lost my records. Kudos on the customer service. P0305 is gone. Still have bank 2 lean, P0174. Did find a post to change PCV valve, next cheapest option. Will continue to update. Problem is intermittent now. Comes and Goes.

Thanks

Check out this link:

http://www.obd-codes.com/trouble_cod...gen-sensor.php

Dan

[Beavx]

OK, found a bad pcv valve, collapsed vacuum hose. Replaced that. Code still existed. Move injector to different cylinder. Didn't clean it, just gave it a tap. Earased codes. Ran a full tank of premium w/ Seafoam. Then ran a half tank with Lucas fuel treatment. No code or problem for a week straight. Found out injectors are a common problem with these Windstars. New injectors are 30$ each at Millineum Ford. y2kford.com.

Problem seams to be solved.

[bbrigham]

I recently got p0302 cylinder 2 misfire on my 2000 3.8 .
I changed plugs, wires and coil pack and still got the code.
I being lazy and cheep took a short cut to cleaning EGR. ports.
I removed wipers cowl and cover very ease to do.
Then removed upper intake cover, air filter and EGR valve.
Then I took a household canister vacuum with that plastic long skinny end witch now one knows what it is for anyway, and put it next to the EGR port as I picked at the build up with a dental pick.
Then I vacuumed out the port where the EGR valve goes.
Worked great will let you know if code comes back as I am going on a road trip this weekend.
Bill
ps all ports were pluged except cylinder 2 causing all exhaust gas to go to cylinder causing missfire.

[Beavx]

Follow up:

Almost three weeks, no codes, plenty of power. I suspect that among all the things I replaced, the injector on cylinder 5 was stuck or dirty. The code usually came up in 24hrs. Needless to say, I have plenty of power, gas mileage is back up, Traveled over two hundred miles this weekend for vacation, NO CODES. Thanks to everyone in the forum for the input shared.

I do suspect, if the code comes back up, I will replace the injector.
BTW: 30$ at y2kford.com.