Cold start stumble
06-14-04, 07:19 AM
#1
Rookie
Thread Starter
Cold start stumble
Looking for diagnostic ideas on an engine startup stumble...
Description: '97 LS400 stumbles (1 or more cylinders missing) on cold start. About 3-5 seconds and then all 8 cylinders are hiting smooth. The colder the engine the longer the stumble. Warm starts are not an issue.
There is never enough time to check which cylinder(s) are causing the problem via manual (pulling the plug wire) method. The engine never misses a beat on the road. I log mileage and it has remained steady at 23-24 (rural commute.) Caps/rotors are fairly new (but I cleaned them anyway.) The plugs look great (color match is perfect) and I have run a couple brands of injector cleaner through (1000% overdose... several bottles in 1/4 tank of gas.)
Any suggestions or similar experience would be appreciated!
Description: '97 LS400 stumbles (1 or more cylinders missing) on cold start. About 3-5 seconds and then all 8 cylinders are hiting smooth. The colder the engine the longer the stumble. Warm starts are not an issue.
There is never enough time to check which cylinder(s) are causing the problem via manual (pulling the plug wire) method. The engine never misses a beat on the road. I log mileage and it has remained steady at 23-24 (rural commute.) Caps/rotors are fairly new (but I cleaned them anyway.) The plugs look great (color match is perfect) and I have run a couple brands of injector cleaner through (1000% overdose... several bottles in 1/4 tank of gas.)
Any suggestions or similar experience would be appreciated!
06-28-04, 08:23 PM
#3
Rookie
Thread Starter
Update
There has been an improvement since the second round of injector cleaner. The stumble certainly feels like a "leaky" injector is taking a moment to build pressure.
Round#1 - 4 12oz bottles of STP fuel additive in 1/4 tank of gas.
Round#2 - 4 12oz bottles of Berrymans injector cleaner in 1/4 tank of gas.
Both times I ran it until the low fuel light came on. Think I will try a third brand of injector cleaner. Doesn't cost much to try.
Must also consider that summer is here. My "improvement" might just be the warmer weather. Anyone know if there is a cold start injector/enrichment system on the LS400? Any diagnostic recomendations?
Round#1 - 4 12oz bottles of STP fuel additive in 1/4 tank of gas.
Round#2 - 4 12oz bottles of Berrymans injector cleaner in 1/4 tank of gas.
Both times I ran it until the low fuel light came on. Think I will try a third brand of injector cleaner. Doesn't cost much to try.
Must also consider that summer is here. My "improvement" might just be the warmer weather. Anyone know if there is a cold start injector/enrichment system on the LS400? Any diagnostic recomendations?
Thread
Thread Starter
Forum
Replies
Last Post
geekrunner
ES - 1st to 4th Gen (1990-2006)
1
08-25-17 04:48 PM
m1k3yg
GS - 1st Gen (1993-1997)
1
10-04-12 05:35 AM
