Car randomly dies sometimes.

Kevin Matthew Sousa

New LVC Member
Dec 25, 2013
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My car will sometimes start to idle low/rough and die when coming to stops/turns. Any idea what can cause this?
when was the last time that you changed your spark plugs and wire or coils since you didnt specify what year your car is if its a 97-98 it has coils. Also check your (MAS) Mass Air Sensor, and also your Throttle Position Sensor, (TPS). Also sometimes washing it makes it run better.
I had a problem where mine would die in similar low idle situations where you would suddenly step on the gas and it would die. Turned out that my throttle body gasket was mostly disintegrated/not there. New 40 cent gasket cleared that up for me.
Wow. I'm having exactly the same problem. New MC IAC, new TPS, new throttle body gasket, new MC coils and plugs, new alternator. It started with running a little crummy and surging at idle and then escalated to dying occasionally. I replaced the fuel filter the other day although it was supposedly done at my shop. I doubted it when the filter was from 2011 and it was theoretically done this year. Replaced the ground wire on that side since I was there and upgraded to four gauge which is what I used in my stereo install.

This whole thing started when I put the car on rear ramps to adjust the rear ride height sensor. No codes and Lincoln couldn't even figure it out. Car runs like a top on the freeway. The weirdest thing is that the car was running great and I didn't change anything. I thought it was bad gas and seafoamed everything. It ran better for a while and now it's worse. It's driving me crazy. I wonder if the fuel pump is checking out?
Run the engine at idle and take a propane/map gas torch and hold it near all the vacuum lines, listen for the idle to raise. That'll give you an idea where there may be a leak.
Thank you everyone for advice! Its a 97 and plugs and coils were done like 12k ago. I just did rememeber I have a bad vaccum line I taped up. That might be it. Car randomly does this thought but could be it.
Still not able to locate the problem. Almost all of my vac lines are new. Brake booster, no, but no increase in idle occurred. My friend's car in Ventura just started doing the same thing and he is all stock. My roomie's 98 did the same thing the other day. Only common denominator is fuel. I suspect that Cali may be in the process of increasing the ethanol in fuel which I read about some time ago. Maybe I should be adding octane boost and see if that changes anything. Enough to make a difference? I don't know. But I'm not sure there was ethanol in the 93 I was able to use in 1997.
easy check, next time, buy gas from a different oil company.

btw, i had to retorque all my intake bolts after changing the intake gaskets. set them with a torque wrench, and they were loose a week later. aluminium changes shape a lot with heat, and that's why you check the lug nuts.
Thanks, Chris! I switched exclusively to Chevron since the issue began, so have done that. Also, awesome advice on the intake bolts. I will definitely check those again. :D
Thank you everyone for advice! Its a 97 and plugs and coils were done like 12k ago. I just did rememeber I have a bad vaccum line I taped up. That might be it. Car randomly does this thought but could be it.

You taped up a vac line... stop being cheap
This may be the last thing to ever go bad, but when my car was randomly dying on me, it didn't matter if I was idling, slowing down, driving on highway, etc., the engine would go into an extreme lean condition where it wouldn't get it even run under normal throttle/idle.

I wasn't getting any codes either which I thought was really weird. I made a correct assumption that the PCM was going bad and replaced it with a used one. So far over a year now and never died again.

Take your time and don't go crazy replacing everything. The only other thing I changed was the fuel pump module in the trunk with a newer, 03 Cobra module which plugs right in.
I had exactly the same problem on my '97 LSC. It turned out to be a vacuum leak on the PCV lines that go into the intake near the throttle body. There's a "T" connector there and the lines had dry rotted and were sucking vacuum. I replaced the hoses and the "T" and fixed the problem. That may be your issue, or it may not. But that worked for me. :)
I have braided ss hoses there and a brass tee. Just for giggles, I went back to brand new standard setup with hoses, tee and PCV. Fortunately there was no change because I love my hoses and purple finishers. :p My screenshot. Lol

Well, after going through all the bolts on the upper and lower intake, I found one in center driver side where the miss was occurring and I got probably two turns on it. So far so good. Will report back soon.
Issue came back after an extended period of idling. I have an ECU on the way. I'm beginning to run out of things that I can do. Maybe fuel pump? Damage to the wiring harness on that side?

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