My wife's car has right bank misfires, intermittent and just at start up. Poor gas mileage. Mechanic believes either injectors or coils. Anyone know Ford substitute coil pack part no. and if they will work? Thanks.

 

i believe the ones for the lincoln ls also fit s type.

 

I'm sorry man you are not being very clear. You are saying that only one bank misfires, in other words 4 cylinders which all happen to be at the same bank randomly misfire? If that's the case I doubt is the coils or the injectors unless you changed the injectors and the coils on the opposite bank already, which I doubt. Your mechanic doesn't sound very smart either.

Using a bit of logic, the problem should be on something common to all the cylinders on that bank, like an Oxygen sensor for example. The coils on these car do go bad but its weird to have only misfires on one bank. If not the O2 sensor which is the most likely, plugged catalitic converter could be the cause. Do you have codes so we can help you?

 

Codes have been p 301 03 05 typically. Misfire occurs at start up. Changed fuel filter and plugs. Everything was dry. After plugs filter change, misfire again. Mechanic has Jag software and downloaded data. Misfire occurred at start up. Intermittent occurrence. Before plug change we threw a 1316 code too. Since plug change and running some injector cleaner through gas, misfire has been on on 01 and 03 or 03 and 05 etc. Fuel mileage is poor. My STR is averaging near 22. Wife's 05 is in the high teens. 88k on the car.

Thanks.

 

Last three misfires were 300 301 303, then at a later time. 303 and 305. Last time, 301 303 305.

 

If it turns out to be coils, these were the cheapest I could find at $47.88 with 2% in eBay Bucks...
eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

 

Thanks for the help with the coils. I can understand a weak coil could be under a certain electrical load at start up that could cause it to malfunction and cause misfire. I can also see that the injectors could have issues. When we changed the fuel filter, it was pretty ugly. That theory is that the injector(s) are leaking fuel after the car is shut off, and if the car is restarted before that fuel dissipates, it misfires. I've also been advised vacuum could be a cause, as well as a CAT on that bank.

Also, while I can understand that a coil could cause the start up misfire, I don't understand why, after the car's running, it would be causing crappy mpg. We do know that when we changed plugs, coils were not identified as a problem and everything was dry.

Just as an fyi, what CATS would work well for the non s/c car and are there crossover ford 02 sensors? Thanks.

 

The things it was not likely to be were the plugs. Especially multiple at the same time.

What are the fuel trims for both banks at start up, when warm at idle and when warm at 2500rpm?

I would stop changing parts and instead think. To do that I feel you need information.

 

is that the price for 1 or a pack ? It's not clear on the listing

 

Almost certainly for 1. They're not cheap.

Be careful, for the coils are very different depnding on engine & year. (The 4.0 for example are not like those for the 4.2)

 

Just changed the coils on my 3L V6 today at a price of £10 each from Eurojag, noticed that they have V8 coils in stock for £15 each. OK you will have to pay for shipping but thats the best price i can find if indeed you do need coils.

 

It's one...Prices change all the time, currently rockauto is cheaper by about $50...At 8 shipped for $327.91...

4.0 not the 4.2...

 

Quite.

 

Understood. Thanks, I'll hunt the other threads to see what diag tool I can get to read the fuel trims. I'm running MacBooks at the house so if anything interfaces with a laptop ... needs to be a MAC application.

Cheers,

Rob

'84 XJ-S 3.6 5 Speed Getrag
'03 STR Onyx with Grey Leather
'05 S-Type 4.2 Granite with Dove

 

We put our hands on a scanner and pulled some fuel trim info:


Both banks idle fuel trim is LT is 3.1

2500 rpm fuel trim LT is 0

2500 rpm warm idle both banks ST stays near 0

cold idle trim on ST bank 1 was from 8 to 11%
and ST Bank 2 was half 4 -5 %.

We'll let the car cool off and try it again to get better readings.
We haven't used a scanner before and were trying to find our way
through the menus.

 

Yeah, tools are "fun" to fight

Those LTs look fine, if they're typical. Worth checking again to make sure.

Wiring, a bank-specific problem (EGR? PCV? EVAP? etc), the cat or maybe coils. If it's coils they usually fail at various times and you may feel/hear misfires such as going up hill at say 50mph when warmed up. (You're looking for quite a bit of engine load but not WOT as misfires can't be tested for by the PCM under WOT unless they're abysmal.)

The STs aren't bad, either. Nothing screams air (vacuum) leak, so that rules out a ton of things. (It's fair to say the 3.0's prone to leaks but the 4.2 isn't and even then it tends to be both banks at once.)

Don't panic but a 4.2 with multiple misfires is not something that tends to happen on here so unless a tech helps this could be a struggle....

 

Thanks, we'll check the fuel trims in the morning when she's cold again. Before I shut the car off I check warm LT trim and Bank 1 was 6.4 and bank 2 was 4.7. When I drive the car I'm with my wife and we're driving under light partial throttle and a lot of time in the 1500 rpm range in overdrive and under load, say, going up or down hills the car doesn't feel smooth although there have not been any misfires thrown under this condition. She's only misfired, and intermittently, at start up. Our outside temps here in South Carolina have been unseasonably warm the past week or so. My wife's driving patten during the weekdays is to start the car and drive a half mile to drop off the youngest and come straight home. Depending on her schedule, she'll start up a couple hours later, drive 5 mins, stop and get a cup of coffee, restart and drive 20 mins, some of which is highway, then park.

When we drive on longer trips, the car never gets the rpms really pushed up because of the way she's geared and I doubt my wife's ever stomped on her to have WOT. I was almost thinking the car needs to be warmed up and run at high rpms for a few intervals to perhaps blow her out. We've only put about 3k on the car since we bought it and based on the condition of the fuel filter, it hadn't seen any maintenance servicing except for oil changes and an air box filter. Someone had put in an ill fitting oversized air box filter and broke the plastic clamps. The car could have sucked some crud in via that problem which we've corrected.

 

The air filter housings on these cars often cause misfires when they are cracked or not fitted properly. So if yours is even minorly broken from previous repair attempts it may indeed be your misfire cause, even if you have fitted it with a properly-matched new air filter. The air filter housings must be perfectly aligned and tight with absolutely no gaps or cracks. Many, many posts here over the years from folks with busted air filter housings looking for answers about their misfire issues. They are easily broken by service people being rough and not understanding how to open them. The best way to change your air filter is to remove the air filter housing from the engine bay before you open the lid. There are instructions here on the forum on how to do just that, perhaps in the FAQ section....

 

+1
that could easily be the problem. Maybe it seals a bit better as it warms up. (But it ought to be fully sealed all the time.)

There's a rule of thumb that within +5% and -5% LT trim is OK but beyond that it suggests a problem, and as your trims head towards 0 at 2500rpm that says: air leak. But not a huge one.

If you need to replace any of the parts, one of the wrecker yards will likely be far cheaper than new.

I wouldn't expect that driving pattern to be a problem and the car shouldn't care whether you use WOT or not. (I expect lots of Jag owners don't.)

 

Thanks Gents,

I'm going to give the air box a good look and call Coventry West a call on Monday to see if they have a good used one.