1998 S70 NA Idles rough, stalls when warm.

PLoudin · Post by **PLoudin** » 13 Sep 2018, 16:24

1998 S70 non-turbo. I started the car up yesterday. It was running well as it warmed up I stepped on the accelerator and revved engine to 2500 and let off has, the car idled fine. A few minutes later when temperature was stable I revved the engine again to 2500 then to 3000 and let off gas slowly. When it went back to idle it was extremely rough nearly stalling sounded as of there was a misfire. I was able to get rpm back to 2500 and the car sounded fine as soon as it went back to idle it was rough. When pressing on gas the rpm dropped then caught and ran fine at higher rpm. After letting down it idles rough and stalled. I tried to start and it would not. After an hour I went out and it started again, ran okay until it warmed up again this morning and same issue. Car has no codes, engine light not on. Tried disconnecting MAF and did not make a difference. (Previous owner put in cheap aftermarket MAF about 2000 miles ago.) I will be cleaning throttle body tomorrow it is filthy. Has anyone had this problem? And if so what was it? My thoughts are if not MAF or throttle body possibly ETC or maybe crack in ignition coil. Wanted this car on the road next week. It has 104k miles and mostly original parts. Thanks.

Post by **rspi** » 13 Sep 2018, 17:55

If you disconnected the MAF it should have popped a code. Have you scanned it?

PLoudin · Post by **PLoudin** » 13 Sep 2018, 18:02

I did. It said MAF low current.

WhatAmIDoing · Post by **WhatAmIDoing** » 13 Sep 2018, 22:06

When I had this issue (exactly how you described), it turned out to be a cooked fuel pump relay. Though I wouldn't want to run a cheap aftermarket MAF either. ETC is also a good bet, and easy to diagnose with a multimeter.

valvolvo70 · Post by **valvolvo70** » 17 Oct 2018, 13:46

Hey PLoudin-Have you solved your issue? I'm having somewhat similar issues, if you read my post, and cant seem to find a solution.
David