Intermittent rough engine.....

Joined
Nov 15, 2006
Messages
20
Likes
0
Points
0
#1
I have a 2000 Taurus V6 3.0L flex fuel with 103K miles. I had a tuneup (plugs only) and new fuel filter about 40K mile ago.

The engine runs fine, then will run rough like a cylinder is missing. Sometimes the check engine will flash but not always, and it doesn't stay on. Next morning, or a few hours later, it runs fine for a few days (maybe a week) then runs rough again. It usually starts up fine, and only starts to run rough during idle.

Could this be bad sparkplug? Or is this "intermittent" more likely a wire or ignition coil?

THanks, MIKE
 
Joined
Nov 14, 2006
Messages
4,885
Likes
53
Points
48
Age
118
#2
be clear: because a flashing SES is an indicator of possiable damage to Catalytic converter...


If the light was on very likely there is a code stored in PCM...
Any of thes statements apply- gas milage decrease- power decrease- puff of smoke when starting- fuel smell in oil??

If the light is flashing, I would Ck fuel injectors- leaking - AND yes the secondary ign wires and plugs

Start with checking for codes- in history or pending
 
Joined
Nov 14, 2006
Messages
2,079
Likes
0
Points
36
#3
A flashing check engine light is a missfire.
What kind of plugs was used on last tune up?
Check out codes with a scanner.
Get the tune up end checked?
 
Joined
Nov 15, 2006
Messages
20
Likes
0
Points
0
#4
I checked codes, cylinder misfire. I changed plugs and wires. Took it for a drive, still hesitates a little but not nearly as bad.

I checked the wire connections at both ends to make sure everything is secure, seems OK.

Any other ideas?
 

kev2

wrench
Joined
Nov 14, 2006
Messages
4,885
Likes
53
Points
48
Age
118
#5
what were the codes?

is the check engine light off?

You did use quality parts?
 
Joined
Nov 15, 2006
Messages
20
Likes
0
Points
0
#6
Code# was cylinder misfire #2. I used the platinum plugs. Check engine light is off.
 
Joined
Nov 14, 2006
Messages
2,079
Likes
0
Points
36
#7
Like motorcraft the motorcraft book calls for or the bosch midnight specials?

Work on cylinder 2 miss.
Got compression.
Good hot spark to plug?
Motorcraft spark plugs?
Is the spark plug wet or dry on no 2 cylinder?
Try switching plugs and wires with another cylinder and see if the miss goes to the other cylinder.
 
Joined
Apr 2, 2008
Messages
10
Likes
0
Points
0
#8
$. 02
If you only did plugs, you may also want to check your wires to be certain they are good. How long has it been between wire change? Misfire can be anything to do with spark, fuel\air ratio, compression, vacuum leaks. Distributor? (cap and rotor)

Another idea if running rough might be plugged injectors, not sure about the 2000 model, port injection or throtle body injection? Quick cleaning of the throttle body or using a good bottle of injecotr cleaner in the fuel may also eventually help.

Good luck!
Bruce
 
Joined
Nov 15, 2006
Messages
20
Likes
0
Points
0
#9
Thanks to all so far for the help.....


P0305, cylinder 5 misfire is current code. This appeared shortly after the tune-up with quality parts and re-check of connectors.

Check engine light is ON but not blinking. Engine is running rough at idle, but seems better at higher speeds (car has good acceleration).

Today I tried a new Mass Airflow sensor, because the mechanic said the MAF was bad (he wanted $400, I put a $140 refurb unit in there). Not much help. With the engine running I disconnect cylinder 5 fuel injector electrical connection and the miss was worse.

I don't have a good way to check compression. I could move the cylinder 5 plug and wire to another cylinder and see if a new code comes up.

Thanks again all.....MIKE
 
Joined
Nov 14, 2006
Messages
2,079
Likes
0
Points
36
#10
Switch plug and wire and see if it moves.
Check and see if plug is wet or dry.
let us know how it goes.
Crunch
 
Joined
Nov 15, 2006
Messages
20
Likes
0
Points
0
#11
Thanks Crunch....

I cleared the P0305, if the same code comes back I will switch plug/wire, clear, and see if it moves. I'm a little frustrated that the shop that did the tuneup didn't try to replace the plug to see if it was cracked/damaged.

On the MAF, is there any "reprogramming" required to make the new one work? This change (recommended by mechanic) didn't help.

Also, I checked DPFE sensor lines (one looked loose) and one port (plastic version, replace at ~20k) is cracked. No code on that yet, but I would guess that needs replaced. Could a faulty DPFE sensor be causing rough idle?
 
Joined
Nov 14, 2006
Messages
2,079
Likes
0
Points
36
#12
Yes .
The DPFE sensor controls egr valve operation.
Also any vacuum leaks.
Good luck
 
Joined
Nov 15, 2006
Messages
20
Likes
0
Points
0
#13
Crunch,
I found a DPFE at NAPA for $86, dealer part was $124 so I'll save a little there. Once I get that in and clear codes I'll check back in.

I'm reaching the end of my expertise, and time. Problem is I'm not sure if I trust the shop that did the tune-up since he suggested replacing the MAF to fix the cyliner 5 misfire. He said there was a code for this, but I haven't seen it pop up when I check. I tried a MAF from a friends car (same engine) and it didn't perform any better.

Could the ignition coil cause this #5 misfire? I know, it could be alot of things. A mechanic told me a year ago that I had a "miss" (I was in there for routine maintnance) and he swapped out my ignition coil with his and fixed it. He offered to sell me his for $100, even though I didn't notice any problems before (or after until now, 1 year later).



THanks, MIKE
 
Joined
Nov 14, 2006
Messages
2,079
Likes
0
Points
36
#14
If the miss fire is just one cylinder no on coil.
Check plugs and wires and cap and rotor and injector and compression on that cylinder.
Crunch
 
Joined
Nov 15, 2006
Messages
20
Likes
0
Points
0
#15
Crunch,
OK, so a bad coil likely would not cause just the one cylinder misfire.

Cap and rotor? I thought the coil pack was in place of this?

New DPFE didn't totally eliminate problem, but at least it isn't causing more. No code yet, but still runs a little rough at no load (either idle or cruising speed). Acceleration is fine, no real loss of power.

I'm going to try new plug in #5 and check remaining vacuum lines, and if that doesn't help I will get the $60 injection system clean at the shop.

Thanks again, I'll post my results......MIKE