2001 Taurus misfiring in idle?

[jbeer32]

Hello. I have a 2001 Ford Taurus with a 3.0. Last couple of weeks it has been 'misfiring' in idle. When I start up the car, the engine shudders and shakes randomly like extra random heartbeats. When I am driving, there is no problem and the random shaking goes away but if I come to a stop light or sign, the engine will randomly shake again. Does not seem to affect the driveablilty of the car but is worrisome regardless. My check engine light has been chronically on for about a year but had a buddy run the code and it is due to a bad seal on my gas cap. I was wondering if it is due to a bad spark plug(s) or plug wire(s). Anyone with any insight?

[chartmaker]

Originally Posted by jbeer32

Hello. I have a 2001 Ford Taurus with a 3.0. Last couple of weeks it has been 'misfiring' in idle. When I start up the car, the engine shudders and shakes randomly like extra random heartbeats. When I am driving, there is no problem and the random shaking goes away but if I come to a stop light or sign, the engine will randomly shake again. Does not seem to affect the driveablilty of the car but is worrisome regardless. My check engine light has been chronically on for about a year but had a buddy run the code and it is due to a bad seal on my gas cap. I was wondering if it is due to a bad spark plug(s) or plug wire(s). Anyone with any insight?

I have '01 and '03 with DOHC.

The '03 has a random misfire and less than smoothe idle but at the correct speed when first started, and sometimes at an warm idle. Never at any throttle pos above dead idle. AM Radio noise check shows no uneven pops. Acts like lean, but no leaks can be found.

Weird thing is, it does not do it if the A/C is off. I switched IAC between cars and made no difference. Next I will switch MAF, That also is an easy switch.

If you find an answer, pass it on.

-chart-

[sheila]

Might run the code(s) again (free at autozone). Which engine? Vulcan or duratec?

[crackhead]

chartmaker,
you probably need to replace the PCV valve and intake manifold gaskets.

Jbeer32,
replace your gas cap, and check the codes for anything else. FYI: a the evap system is important because the motor pulls a vacuum on it and if there is a leak then it will reduce the vacuum in the system.
I am also betting you are having other vacuum leaks.

[TJVJR]

^ Very good advise , any air that is not properly metered will cause the issue you described. I recently had to replace IM gasket to correct a similar problem , not saying for sure that is your problem but do replace cap and if the problem persists check for vacuum leaks.

[chartmaker]

Originally Posted by jbeer32

Hello. I have a 2001 Ford Taurus with a 3.0. Last couple of weeks it has been 'misfiring' in idle. When I start up the car, the engine shudders and shakes randomly like extra random heartbeats. When I am driving, there is no problem and the random shaking goes away but if I come to a stop light or sign, the engine will randomly shake again. Does not seem to affect the driveablilty of the car but is worrisome regardless. My check engine light has been chronically on for about a year but had a buddy run the code and it is due to a bad seal on my gas cap. I was wondering if it is due to a bad spark plug(s) or plug wire(s). Anyone with any insight?

My '03 similar, random misfire at dead idle, but perfect running anything above idle.

Checked plugs, wires, coil pack, IAC, in fact switched things from my '01 to the '03 with no change at all, No codes. Added a vacuum leak by pulling a hose and it did not create the kind of rough idle I see. I took an old propane torch and removed the jet, put a hose on it and let propane go into the vacuum leak I made, and it did not change the rough idle. Momentarily increased speed.

However, in thinking: I pulled the hose on the EGR and put a hose on it, sucked a slight pull on it and it made it much worse. So here is the thought, any leaking of the EGR at idle will make a rough sometimes miss at idle. At any speed over idle the EGR opens and the engine system expects EGR flow. Not at idle.

So, here is one thing that could explain rough idle, but no issue above idle.

Next plan is to replace the EGR valve.

Will get back on this one.

-chart-

[jbeer32]

I just got back from autozone who ran the check engine codes for me. The code read Cylinder 1 misfire, code P0301. Would this most likely be due to a bad spark plug or wire? I know I should and will check all plugs and wires but how can you determine which cylinder is cylinder 1? Thanks everyone!

[chartmaker]

Originally Posted by jbeer32

I just got back from autozone who ran the check engine codes for me. The code read Cylinder 1 misfire, code P0301. Would this most likely be due to a bad spark plug or wire? I know I should and will check all plugs and wires but how can you determine which cylinder is cylinder 1? Thanks everyone!

#1 is pas side, back bank (firewall) either engine.

However, you better replace all the plugs at once. If the wire for that one is damaged, or has open circuit by the ohm meter, you can replace just one wire, but likely, if one is bad, best to replace the set.

Then you need a diagram of the coil cyl numbers and engine cyl numbers. Replace one at a time so as to not get lost.

-chart-

[ellmarsh420]

i had the exact same problem with the shaking in a 2000 SE, had the spark plugs and wires replaced as well as a transmission service and it was fine.

[chartmaker]

Originally Posted by jbeer32

I just got back from autozone who ran the check engine codes for me. The code read Cylinder 1 misfire, code P0301. Would this most likely be due to a bad spark plug or wire? I know I should and will check all plugs and wires but how can you determine which cylinder is cylinder 1? Thanks everyone!

Single misfire likely plug, plug wire, injector.
If it has 2 and they are partners (like 1-5) then likely coil also.

Hard to understand plug or wire misfire at idle, but not at hard load. Spark jumps easier at low compression, like idle throttle. Last time I saw open wire, missed only at full throttle, but was getting progressively worse.

-chart-