fordfan66

After getting trouble codes on 4 and 5 I had all my plugs (except #4) and replaced the #4 COP. It felt better but not perfect and I ran it on a 1000 long distance round trip. The trouble persisted, but I feathered my way through driving as described below. When I got back the trouble codes were P0430 (bank 2), P1309, P0304 (misfire 4) and P0305 (misfire 5). I put what was in the #4 COP into the #5 COP. That seemed to be better, but still has running problems. The biggest symptom is the car seemingly missing or running rough when you hit the gas at different speeds. No codes now, but the rough when I hit the gas problem is still there.

History: 5.4L, 4WD 1998 Expedition. For the past 100K or more, there is a crack in the exhaust manifold on the passenger side, you can hear a tick from it. I have run this expedition, usually with a small trailer, for at least 50K per year. It had the transfer case replaced last year, and one time 5 years before that. I bypassed the heater core last week. Have only run synthetic oil and changed it maybe once every 10 or 15k. It leaks a little oil (there is now a little spray under the hood on driver side), so I have to put in another 5 quarts every 10k.

For the last year or longer, my 98 Expedition seems. to shudder when you hit the accelerator after it gets going 20 or 30 mph and at various other times. Changing the transfer case didn't matter. So I'll accelerate normally with what feels like a miss or two up to 40. Then I can't press the gas too far past just touching it before the car shudders and misses. So instead I'll 3/4 floor it to make it downshift, ride 2nd gear to 3500 rpm to get to 50, then back off to let it settle into drive. Overdrive is the same thing. I'll be going 55 and have to downshift to bump it up to 60 or 65, then back of and let it cruise. Its worse when towing, and I do tow a lot. When I am cruising, the Expedition is only comfortable just touching the gas, pushing down causes problems. Its very smooth going downhill, and occasionally settles into smooth running, but most times I have to feather the gas. It tows a lot as I regularly move 1000 lbs on a trailer.

What should I test or look for to get her running reliably?

Tackle

I understand not everyone has the same mechanical aptitude but this is basic 101 stuff.

If you have 2 items that are bad and causing issues why would you swap them and expect a different outcome?

The troubleshooting step is "Good for bad", not "bad for bad". I have no doubt it did not run any better.

Swap the # 4 and #5 coil with #1 and #2, then see if your misfire moves to those 2 cylinders (you might get a code or you might not).

Otherwise purchase 2 new COP's and replace #4 and #5.

I'm leaning towards this being your issue with the shaking and shuddering issue, but it is not the only possibility. Please fix the known issues and report back as to any current issues.

fordfan66

UPDATE: I put a brand new coil pack in #5, and big shock, it runs much better. It still has a slight problem that I'm sure was adding to the marginal coil pack on #4, and a worse one on #5.

Now to get the car up to speed, once it gets to 40mph, I have either had to hit the gas or just slightly feather the gas pedal right near 0 pressure on it, so the first inch or two (I did this with the bad packs and it was hard to get the Expedition past 55mph). So after the 2 coil packs, there is no missing at low speeds or idle, but the engine still has problems accelerating after 40 mph up to 55 to 60. With a trailer its worse, and when it goes into overdrive around 60 to 65 it wants to slow down. This is because when you press the pedal down past an inch or two, the engine sputters a bit and has trouble. Pushing the pedal way down to downshift gets past this, but the sputter is still there, just drowned out by the power.

I have not cleaned the throttle or MAF pretty much ever, but certainly not in the last 100K. I have replaced the air filter twice this year, the last one about 4 months ago (both desperate attempts to fix the I know now COP problems). So I will get some throttle cleaner soon and take a look after I look up a good thread just to double-check a complete way to clean them. But feel free to post a good throttle cleaning link thread to me.

Thanks and please give advice on how I can get her running well besides cleaning the throttle and MAF and/or what to look for.

cptBudd

throttle body cleaning how to:

http://www.fordf150.net/howto/throttlebodyclean.php

biglee88

Check fuel pressure and replace fuel filter. Run a compression test just to make sure the internal parts are good and in working order. You did change all the plugs right? And if you have been running with a bad miss for several thousand miles your cats are probably toast

fordfan66

Yeah, I've had misses on and off that I thought were tranny problems and then 10,000 miles later I'd replace a COP and it was fine.

If the Cat's are toast can I replace them with "resonators" or pipes in the short term so I don't ruin a new set? I might build a set were I could take them on and off, guess it's just a matter of plumbing. But won't I have to make and O2 sensor fix to do that too?

akdoggie

Tackle is spot on. You are trying to fix something with something that needs fixed itself. I personally would do a compression test on the engine with this many miles. No reason to throw good money after bad. Your engine has served you well. Better than you deserve actually. You have pushed this poor thing to its limits and it keeps going.

Do a compression test. If those cylinders are up to grade, then save yourself time and energy, get 2 COPs and 2 new plugs. If the compression is down, there is no fix, other than major repairs. Your codes say what is wrong. The computer doesn't lie. What it says is gospel, and needs to be repaired accordingly. That is why the OBD II port was created. To fix things. Good luck.

bubbabud

With that mileage it could be just plain wore out. you might consider an upgrade to a couple of 100,000 newer because at this stage in life it will become a money pit.

fordfan66

" Better than you deserve actually."

Really? So my expedition should have failed by now and I don't deserve it lasting? How about wow, that's great to get that many miles and at the rate your going I hope you get 500K, because that' what I'm thinking. I want help figuring out why now it stumbles and sputters from 40 to 65. Your advice concurs with the first reply, and I can report after I find time to clean the throttle and sensors, possibly also removing the CAT's from the equation by bypassing their signals with a MIL eliminator.

akdoggie

I said that for a purpose. You have an engine with 375k on it, and it has treated you well. You said that you have driven it like this for XX number of miles in this condition. That is my reason for the comment. These engines have CEL's for a reason, and those help get your truck to those 375k miles. Prior to these systems, you could get away with misfires and etc, because of the simpleness of them. Now its not the same as the 50-80's. These are high tech now. You can't let a misfire continue, unchecked, or you will ruin an engine or destroy something else, vital to their existance. You also said you ran it this way for over a year.

And you question why I made that comment?