Rough idle at start

[Trotti]

I have a 2000 Ranger 3.0L V6 with about 105k miles on it. Recently, my truck began to idle very poorly when starting cold. I have quite a few symptoms to help diagnose this, so please bear with me. The idle on cold starts is rough, gurgling, it almost stalls (and sometimes does) and the exhaust is unbearable until the engine smooths out (not sure if the smell is really rich or lean, but it smells as if you've got your nose next to the tailpipe while it's idling rough). After you run it for a few minutes - flawless idle and the engine appears to be working perfectly fine. Sometimes, the "transition" happens while at idle. It's rough - rough - rough and then all of a sudden it's smooth without any revving. The time it takes for it to smooth out varies wildly (this morning I made it all the way to work, about a 10 minute drive, with it idling like crap). There is no noticeable power loss at speed.

I've cleaned the mass air flow sensor, idle air control valve, replaced the DPFE sensor, plugs, wires, fuel filter, air filter, and just about everything else I can think of.

One possible culprit, although it seems unlikely to me, is the ORIGINAL, Ford battery that STILL starts my truck. For whatever reason, miracle of miracles, in the nearly 11 years I've had my truck, I have never replaced my battery - but it starts just fine and I've never had an issue (spent 3 hours with the radio blaring the other day and it started right up without issue).

Any ideas?

 

[TomB1269]

Try a new IAC valve (idle Air Control) cleaning can help but if the resistance is off it will not work right, and the symptoms you reference point to the IAC, particularly if you have a stick. (IE Idling on the way to work). If not a stick, then does it idle rough in drive? If not then it is the IAC. Sticks use the IAC when the clutch is in, autos only use it in Park (maybe neutral as well) but in gear they use the TPS for engine speed.

 

[Trotti]

Yup, its a stick shift. I'll pick up an IAC valve tomorrow and give that a shot, I hope you're right.

I'll post an update.

 

[Sasquatch_Ryda]

My 97 3.0L had very very similar symptoms. It turned out to be the EGR vacuum solenoid.

Try unplugging the vacuum line that goes to the EGR valve before you start it. If it runs better its most likely the vacuum solenoid.

The solenoid looks like this

and should be on the passenger side of the engine.

 

[Trotti]

Both of these parts (the IACV and the EGR Solenoid) are pretty cheap. I'll replace each one at a time and update on whether or not either helps.

Although this is a pain in the a$$, replacing $30 parts here and there sure beats a car payment each month.

 

[Sasquatch_Ryda]

Like I said, just pull the vacuum line off the egr valve and if it runs good you've pinpointed your problem. Then there is no need to waste 30 bucks.

 

[Viper Command]

How old are your O2 sensors?

when mine where acting up, it idled like it had a mean cam, but when it warmed up (3-5min)it smoothe out.

 

[Trotti]

I think I may have figured it out with the help of Earl43P. I primed the fuel system by turning the ignition on (without start) twice before starting and now, for two straight starts that would usually cause a problem, the rough idle lasted for only a couple of seconds.

I'm going to start with another fuel filter (replaced about 10k miles ago) and some fuel injector cleaner, and then work my way back until I figure out the problem (dreading doing a full clean or replace on the injectors or a new fuel pump and hoping to avoid it).

I'll continue to update. If it starts just fine after a prime today after work, I think I will have narrowed it down to a fuel system issue.

I used a fuel filter bought at Advance Auto Parts, any idea if those are unreliable? Suggestions for best fuel injector cleaner to try?

 

[TomB1269]

I have like the results from Lucas. Also have you Seafoamed your engine yet to clean out intake and carbon deposits?

 

[Trotti]

Went through about 2 bottles of Seafoam about 10k miles ago when this first showed up (the problem has gotten progressively worse).

 

[Trotti]

We may be right back at square one - the priming process didn't work last night or this morning.

This is an elusive problem. I'll get around to testing the EGR solenoid and IACV theories this week (by disconnecting the solenoid rather than replacing, as suggested).

 

[multiranger]

My 4.0 idled ruff and I cleaned the MAF Runs smooth as a Linclon now.. From what I read just the smallest piece of trash can throw the MAF into fits on a Ford... I used CRC MAF cleaner...

I am assuming you don't have the CE light glowing...

 

[Trotti]

No check engine light at all. Every once in awhile the problem gets so bad that I'll throw an EGR flow excessive code, but that's because sometimes the idle never smooths out for some reason.

 

[Earl43P]

An easy way to rule out excessive EGR flow (stuck open solenoid) is to simply remove the vacuum line from the EGR valve itself. Drive it like that even though it will eventually throw the CEL.

If that works, you need a new EGR solenoid valve.

 

[Trotti]

It looks as if it was the EGR Solenoid as Sasquatch said from the start . . . I took the vacuum line off of the valve and it cranked up fine. Put it back on, started the engine and it stumbled, stuttered and almost stalled. While still running, I removed the vacuum line from the EGR valve again and it smoothed out instantly. I replaced the EGR solenoid and, so far, it has started right up without issue.

I hope this is it - I could use a few thousand miles without any issues.