Intermittent fault causing me angst
Thread Starter
Instructor
Joined: Jul 2008
Posts: 158
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From: Hobart, Tasmania & Darwin, NT
Intermittent fault causing me angst
Hi all, yet another intermittent fault thread :-(
My car has been faultless for years and then recently imploded its air flow meter which was replaced and fixed that problem. Unfortunately a new problem has emerged since then. The issue is that in the morning (only) on the first start up of the day that the car will have a cough as it trundles down the driveway at 2-3000rpm, then will hit 2200-2400 rpm, revs will suddenly drop to stall unless I unload the engine with the clutch at which point it will bounce back up to 2300 then drop again. The car surges like this no matter what you do with the throttle and will not rev higher than 3000 rpm. If I turn the car off, leave it alone for 5 mins then come back it starts perfectly and is faultless. It currently happens 3/5 mornings, some damp some dry days, no rhyme or reason, but only early in the am.
My mechanic can't get it to fault when he has the car, and the hammer has given no info to trace it.
Car has fresh DME (actually has had 2 just in case), has had the new AFM changed out to another one, but to no avail.
As a simpleton it strikes me that an engine requires fuel, spark/ignition, air in, exhaust out and compression to work and that the most likely issue here is ignition - just not sure where in the system to go looking.
I'm a vascular surgeon and need a reliable car to get to work in a rush if I need to so am getting really nervous about my daily driver being not as reliable as previous. I'd love any thoughts.
Mark
My car has been faultless for years and then recently imploded its air flow meter which was replaced and fixed that problem. Unfortunately a new problem has emerged since then. The issue is that in the morning (only) on the first start up of the day that the car will have a cough as it trundles down the driveway at 2-3000rpm, then will hit 2200-2400 rpm, revs will suddenly drop to stall unless I unload the engine with the clutch at which point it will bounce back up to 2300 then drop again. The car surges like this no matter what you do with the throttle and will not rev higher than 3000 rpm. If I turn the car off, leave it alone for 5 mins then come back it starts perfectly and is faultless. It currently happens 3/5 mornings, some damp some dry days, no rhyme or reason, but only early in the am.
My mechanic can't get it to fault when he has the car, and the hammer has given no info to trace it.
Car has fresh DME (actually has had 2 just in case), has had the new AFM changed out to another one, but to no avail.
As a simpleton it strikes me that an engine requires fuel, spark/ignition, air in, exhaust out and compression to work and that the most likely issue here is ignition - just not sure where in the system to go looking.
I'm a vascular surgeon and need a reliable car to get to work in a rush if I need to so am getting really nervous about my daily driver being not as reliable as previous. I'd love any thoughts.
Mark
IHI KING!
Rennlist Member
Rennlist Member
Joined: Aug 2001
Posts: 13,400
Likes: 229
From: Nashua, New Hampshire, USA
This sounds very similar to this thread which was traced to a bad coil
https://rennlist.com/forums/964-foru...-rpm-help.html
https://rennlist.com/forums/964-foru...-rpm-help.html
