My 97 expedition has a miss fire. was told by canadian tire that it was something wrong with the engine, meaning it was no longer any good. i changed the coils and the wires as well as the plugs, the vehicle got better but not smooth it still has a miss. when i changed the plugs i noticed that there were a few that appeared green in color as if it was burning anti freeze but it is full in the bottle. was told it may be the valves in the head due to carbon build up. i bought this rig for my wife and would like to know for sure what is wrong. is it spark, is the motor gone, is it the dome gasket, or is it burning coolant.

NO ENGINE TOLD AND IS AN ENGINE + EFI PROBLEM.
4.6 or 5.4L v8
sure 50 causes and up to 20 tests to find it.
GUe$$ing is super expensive and labor max.

if engine is good ,22 years latter, and passes compression tests.?
why not t scan he PCM FIRST and see DTC ERROR CODES.
LIKE (AND MORE)
P03XX CODES,. FOR ANY KINDS OF MISFIRE????????
new spark plugs and new COP boots < they do not lat 22 years. sorrry
boots are $2 each at rockauto.com

IF SPARK IS GOOD THEN CHECK FUEL PRESSURE

THE FPR IS PROBABLY BAD, OR INJECTORS CLOGGED OR LEAKLING
THE PCM IS CAUSING THE SURGE, ON A HOT ENGNE
THE PCM JOB OF MANY IS TO CONTROL IDLE, AND SINCE IT CAN NOT GAIN CONTROL OF IDLE IT HUNTS IT OVER AND OVER TO ATTAIN IT.
see seems crazy but that is how \it works. fix the engine power loss first

Yes EGR must not stick open ever at idle or it will hunt or stall.



THIS IS NORM\AL, FOR ENGINES GROSSLY MISFIRING OR OVER OR UNDER INJECTED GROSSLY'

BAD MPG IS mISFIRING AND OR DUE TO GROSS OVER FUEL PRESSURE
THE SERVICE MANUAL COVERS ALL FUEL PRESSURE TESTS.

Why skip the OBD2 scans/ ???????
what it it told you what is wrong, and you miss all that.
like P0303 error and injector 3 is clogged or leaking.
and the like.

we can rent, barrow,. buy or get the car scanned.
No reason to skip it.
even if no codes show up that MEANS SOMETHING.
top something is fuel pressure wrong, or injectors messed up.

cranks fast? and battery fully charged is the WAY!
Getting gas means, what? how done, ? the dribble test?
FIRE,, what is fire, spark good on all cylinders? tested.
FIre takes 3 things,good compression ,spark then fuel
or no Combustion FIRE.3 things.
no engine told and is an engine question, 3.0L or3.8L?
3.8L V6 I guess and answer now. has 3 sets of dual spark coil packs
that must never be wired up (HV) wrong as many do.
new wire sets plugs are best never this old ever.

push rod valves, cam in block.
connected new battery up backwards or charger up backwards, blows up very expensive electronics.
here is the otto cycle tests, (technolgy)
engine good, compression 150psi up and near equal all.
spark good to all cylinders, tested good.
if get this far, test fuel works for 3 seconds or more.(spray starter)
fuel is last.
3.8L (VIN L, 1 And K) Engine code not told or RPO list 3.8L (VIN B and 3) Engines Firing Order:
the coil wiring is not the same on both engines.
no VIN told
vin B or 3 here
rule 1 replace parts 1 by 1, never in pairs or more or get lost and need this drawing or t he L,1,k) drawing cure that.
test spark 1 by 1. there are 3 coils , firing in wasted spark MODE.

Take it elsewhere, their specialty is tires. Sounds like they are using guesswork

follow the spark plug wires and you will see the spark plugs make sure you remove one at a time.ok hope this helpd you out..

using the wrong oil is "bo...cks.NO SUCH THING.related to the problems you mention,NOW start again,with whats wrong.....???

more and likely water has gotten drowned out one of you coils . this was a problem for ford with water getting around the boots and killing the coil. you can have you check engine light scan at a advance or autozone for free. it should come up with a cylinder miss fire code. post back and let me know.

it sounds like you need to tune up your vehicle. whenever the service light blinks it usually means you have a miss fire. You can take it to auto Zone to retrieve the code. The code should tell you what cylinder is miss firing.Hope this helps. Please leave comment.

You can always get a bad switch out of the box, and that is a pretty common problem on thoes vehicles, Id retest the switch as you are thinking before going elsewhere

Did you by chance check the resistance of your plug wires? They have a tendency of breaking down over a period of time and need replaced. The spark plugs would have told you what was wrong with the engine many times.

you are suppose to use T-IV ATF in toyotas or they will not shift correctly.