I have a 91 Ls400, the last few weeks i have had a miss when running hwy speed. It is just for one second then it may not do again for 2 or 3 minutes or maybe for days or sometimes a week or more. I have ran the gas all the way to empty, then filled up and added injector cleaner, twice, two different kinds even. No check engine light during any of this. Almost feels like plugwire or coil jumping fire. Does any one have a suggestion?

Thanks

 

When was the last time you change your spark plugs? How many miles do you have on your 91 LS400? May need to check you timing belt also? Basically a tuned up may be needed if you have a high mileage LS.

Chu...

 

Tuneup was done about 25000 miles ago. Have about 143000 miles and i just did timing belt about 2000 miles ago.