Problems with low idling and stalling

Status
Not open for further replies.

goodfizzgig

Junior Member
May 1, 2014
2
0
0
I drive a 2002 Mercury Cougar, and recently I've been having problems with the car idling low, and then stalling.

The first time this issue happened, it was only a problem when I had the car in park. I took it to a mechanic, and was told that my intake manifold gasket was leaking. I had them replaced, but had to take the car back the very next day because I was still having the same problem, only worse this time, as now it was idling low and almost stalling even when the car was in drive whenever I was completely stopped. When I got it back they said they "think they got it this time" and didn't charge me anything. The woman at the front desk didn't seem to actually know what they did, and since they didn't charge me I just assumed they had messed something up the first time and fixed it.

My car ran fine for about a week, then one day I left it running while I ran into a gas station, and when I came back out with was idling low and shaking again and stalled when I reversed out of the spot. This time I took it to a different shop, since I was frustrated with the previous one. Basically, they told me that it was still my intake manifold gaskets, and that the previous shop hadn't done the work properly. I had them redo the same work I had just had done. I don't think they were trying to scam me, seeing as they weren't pushy about having the work done there, and asked me if I'd rather take it back to the other shop to be worked on again (most likely free of charge) or if I wanted them to do it, and to try and get my money back from the other place.

I picked it up on Friday. My brother drove it to work last night, and he sits in his car on his lunch breaks. He told me that he turned it on for heat (Illinois, it got pretty cold here again the last couple days), that it ran fine for about 10 minutes or so, then the RPMs started dropping and eventually it stalled and shut off. However, it ran fine on his way home. No low idling at stop lights or anything.

I'm pretty frustrated at this point. I find it unlikely that two different shops messed up the work. Could something else be wrong? Maybe because it has something to do with the cold? Even though this only started in February, and it'd been cold since November and I hadn't had any trouble before that?

I'm going to take it back to the second shop tomorrow. Any insight would be helpful.
 

nerp

Diamond Member
Dec 31, 2005
9,865
105
106
Scan for codes. Could be a sensor acting up, or a sensor is doing its job and indicating a problem. Could be an issue with fuel system, a vacuum leak or any of a number of issues that causes bad idling and stalling. You can start swapping out parts with no real idea of what's causing the problem, or, scan and at least you have a starting point. If your garage doesn't bother doing basic diagnostics and just starts throwing parts at you, I'd find another garage.
 

Vdubchaos

Lifer
Nov 11, 2009
10,408
10
0
a) any codes (CEL)?
b) what was the last time you changed your sparkplugs
c) is this Duratec engine? If it is, check the Intake Runner Control clips at the intake (there should be 2). They rot/break and can cause trouble like this. Also the cable gets worn out on the inside of the Runner control box itself and doesn't open/close. To check this, start the car rev and see if the runner moves after 3500 rpm (rev it).

^^^ above happened to my MPV, which has the Ford Duratec.
 

Midwayman

Diamond Member
Jan 28, 2000
5,723
325
126
I had similar symptom on my car (different make) with a dirty EGR valve. Look it off, blasted it out with brake cleaner to get the carbon out and back to normal.
 

razel

Platinum Member
May 14, 2002
2,337
93
101
Intermittent issues with no check engine codes are the worst problems to diagnose. I usually end up just using it until it outright breaks. In your case, if two shops said the same thing, gasket, and attempted to repair it, then I'd suspect that perhaps, it's not the intake manifold gasket, but bent parts around the gasket or bolts that no longer can be torqued tightened to the right spec.

In my experience exhaust parts rarely are re-usable because of all the heat involved. Parts/screws tend to be rusted or corroded shut. I know... your situation is intake, but you get the idea.
 
Last edited:
Dec 30, 2004
12,553
2
76
I've had this problem on my 2006 tC (camry engine). Cleaning MAF, throttle body made no difference. It's not the gas. No codes. I have no idea and can't figure it out. It's harder to start now, so I just hold the key an extra half second. I don't worry about it now just use till it breaks.
 

Slacker

Diamond Member
Oct 9, 1999
8,623
33
91
When it is idling rough, press the pedal to the floor briefly, what you are doing is cycling the throttle position sensor through its range, see if that temporarily fixes it.
 

bruceb

Diamond Member
Aug 20, 2004
8,874
111
106
Could be the PCV valve and also have the shop check the fuel pressure and pressure regulator.
 
Status
Not open for further replies.