Engine Rough Idle

I've had my 1998 3.8L V6 Mustang for almost two years now. For the past month or so my car has had a rough idle and it occasionally stalls. However, when it stalls, I will turn the key to the off position and then I will restart the car. Most of the time it will run fine for a while before it does it again.

I DO NOT HAVE A CHECK ENGINE LIGHT ON...

Recently, within the past week, I've replace my spark plugs, plug wires, and fuel filter. I've also tested my coil pack with and ohmmeter and all of its ports seem to work fine. I have also done a visual inspection for cracked vacuum hoses. My PVC valve has an old corroded hose that I plan on replacing tomorrow.

I've considered cleaning the MAF sensor, but I've been told that I shouldn't mess with the sensors if I don't have a check engine light on.

I need some pointers. I've done the cheaper maintenance and I hope to not spent a boatload of money trying to figure out what is going solve this frustrating mystery.

BUT, when my car runs, and it isn't idling funky, it's obvious that the car is running better with the new parts.

Dacon said:

Clean your MAF, that can definitely cause those sorts of problems.

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Would the MAF give me these issues even without a check engine light?

Today, I didn't get to the PCV valve but I plan on replacing it as soon as I can.

After I thought about it for a few, I was thinking that the fuel injectors may be dirty. I believe this might be a problem or at least contributing to my idling issue because my fuel filter was extremely old and the fuel that I poured out of it was considerably discolored. SO, I decided to put a can of Seafoam in my tank of gas not expecting a miracle, but hoping it would help break up and flush some of the crap that may be in my fuel injection system.

Is there a way to spray some sort of cleaner directly in the fuel injection unit? I know that with carburetors you can spray the carb cleaner directly in it. Is there a similar process I can do with fuel injectors without causing more harm than good?

I will check my MAF sensor after I fix the PCV valve. I'd just like to finish one thing at a time so that I accurately rule these things out.

Thanks for the pointer. This is definitely a learning experience for me.

I just got finished cleaning my MAF sensor.

After I had replaced my fuel filter last week, my car seems to run A LOT better and it hadn't acted up for 7 or 8 days until last night and the same exact symptoms occurred. So, I dealt with it the same way I did in the past. I turned the key to the off position and then retried to start my car. It worked. So today, I decided to clean the MAF sensor thought when I did a visual inspection, it looked fairly clean.

Now, I have grown to be almost completely convinced it's my injectors. Would you think it would be wise to let Jiffy Lube work on my injectors? I hear pretty shady stuff about them. The only time I go their is to get an oil change and that's only because I live in an apartment and I don't have any space to do it myself. If so I'll question them. If not, is this a service that a typical car shop can offer? I'm kinda nervous about doing something like that to my car by myself because I haven't worked on injectors much. I'm still new to this car thing

Thanks!

This may or may not be a dumb question. BUT, this is the PVC valve correct? I've been reading the Haynes instruction manual and it says it's on the driverside. But I think this is it. Am I right?

Thanks... Still new to working on my own car. Trying to figure it out.

midsprat123 said:

No, the PVC valve is on the passenger valve cover, at the back. It is a pain to get to, but if you disconnect your intake tube and look under the two coolant hoses going to the firewall, you will see it. On 99-04 SN95s, your picture hows where where the PCV is located due to the redesigned upper engine

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I'll take a look tomorrow. would you be able to send me a picture of the location?