1999 Ford F-150 Misfire Code

ford

#1

Trying to help a friend with his work truck. The truck stopped running a week ago. He had the fuel line checked. He had crankshaft checked. The code he received is misfire. The truck tries to start but doesn’t turn over. He needs the truck for work. A mechanic friend told him to buy new wires and spark plugs. Before he spends more money, I thought I’d ask here for advice. Thanks


#2

C’mon @AudiFlyGuy, this isn’t your first post. You should know we need a lot more info about this truck to even make a wild guess.

Engine? Mileage? OBD codes set? What do you mean “tries to start but won’t turn over”? Turn over means the engine is cranking. So it doesn’t crank? Or it cranks but won’t start?


#3

Can you post the specific code?
example: P0301

CSA
:palm_tree::sunglasses::palm_tree:


#4

Which one of the five engine is installed in this truck?
:palm_tree::sunglasses::palm_tree:


#5

Seems like there is a mechanic to help this person so why are they not taking that free advice ?


#6

If this is the common 4.6 liter V8, a single misfiring cylinder won’t prevent the engine from starting

So I think new plugs and wires won’t change much . . . unless the wires have literally been chewed through by rats :rat:

are you getting spark on ANY cylinders . . . every auto parts store has spark testers, and they’re cheap

Please elaborate . . . fuel pressure at the rail is either correct, or it’s not

Does the engine briefly run with a blast of ether . . . if it does, that will tell you a lot

I don’t know what that’s supposed to mean

Is the engine even cranking over fast enough to start . . . ?

good compression on all cylinders?

Even though this is an uncommon scenario, I’ll mention it . . . I’ve even seen F-150s of that generation fail to start because moisture got into the pcm. There were no codes at all, and I was able to communicate with the pcm. By the way, that pcm DID function after drying it out, and has continued to do so. That was a few years ago, by now. I suspect the vehicle operator was doing something they weren’t supposed to


#7

Ok. I contacted the owner. He does not remember the actual code but googled it and received “misfire.” Truck showed no previous symptoms. When he turns the key, it tries to start but doesn’t. The mileage is 224k. Model year 1999. Engine 4.6 V8.

He said he had the crankshaft replaced. He said the fuel lines and pump were good. This man has limited finances. He paid a mechanic to look at and retrieve codes. The mechanic suggested new plugs and wires. I posted the message to help him get some direction before he spends money perhaps needlessly. This truck is his only transportation. Thanks for your help and I apologize for the late information. I just reached him.


#8

Somebody needs to clarify

The actual crankshaft was replaced . . . ?

If so, why?

It doesn’t make financial sense to replace the crankshaft on a 1999 F-150 with 224k miles

Or was it in fact not the crankshaft itself, but the crankshaft position sensor . . . ?

Again, as long as nobody posts what the actual fuel pressures are . . . key on, engine off . . . all bets are off

what about all those other things I mentioned . . . ?

We’ve given you a lot of pointers, and it should go a long way towards diagnosing the actual problem


#9

Does this have a distributor, with a pickup coil / signal generator /ignition module / ECU inside it? If no spark that’s a part to consider.

If no distributor, then a CPS Crankshaft Position Sensor does that job.


#10

The 4.6 liter V8 doesn’t have a distributor

The engine has 2 coil packs


#11

Folks here are trying to help…

After 20 years and over 200,000 miles there are quite a few possibilities as to why the truck won’t run.

The fact that a mechanic or “mechanic” took a look with the vehicle right in front of him/her and the problem wasn’t obvious then chances are it is going to be very difficult to diagnosis the problem online, especially with limited information.

We can appreciate that this friend needs the vehicle to function and is on a limited budget, but that does not help with the diagnosis/repair.

He, your friend, can replace parts until it runs, but I’m sure he would quickly run out of money and perhaps not get it going. There’s also the chance of creating new problems.

He should find a competent mechanic for a proper and complete diagnosis and repair, but at least needs a professional to pinpoint the fault(s). Spending a little money could save lots of money.

Barring that, in my opinion, all that is left is for him to take some of the suggestions posted here and do some home testing on the Ford, for free or figure out to get a few more bucks to make things happen. If he doesn’t have the ability to do the testing or the work then forget about that option.

I’m afraid he’s between a rock and a hard place, temporarily.

Does your friend have some mechanical ability? Does he work on this truck himself or is he just the driver?
CSA
:palm_tree::sunglasses::palm_tree:


#12

No mechanical ability. He bought the truck about a year ago from a retired gentleman. He has had no issues until now. I’m passing the questions and comments on to him via text. I thank all of you for caring and assisting.


#13

Which is not very efficient for engine problems. If this a really good friend see if he will let you loan him the money to have this repaired properly. Or at least pay the diagnostic fee for him to see if it is even financially worthwhile to repair this vehicle.


#14

Unless the owner can verify SPARK-COMPRESSION & FUEL PRESSURE there’s not much to hang a guess on here.


#15

Spoke to owner. The mechanic who looked at the truck verified that fuel pump was good. Fuel lines good. Coil packs are new (just replaced). Crankshaft sensor replaced (not crankshaft as I stated earlier).
The mechanic verified #3 and #5 cylinders were not getting fire. He recommended replacing all 8 plugs and wires and thinks this will fix the problem.


#16

OK, THAT makes no sense. If only #3 and #5 are misfiring, why replace them all, if the owner is on a budget? Why not swap with other cylinders and see if it follows the parts?

Won’t he feel stupid if the truck still won’t start AND your friend is out money for the repair? I’m thinking this mechanic is throwing parts at the problem and spending your friend’s money doing it. Just my opinion.