Lexus LS 400 Engine Miss

I recently had the water pump and timing belt changed on my 1991 Lexus LS 400. When I picked up the car, the mechanic told me the engine was missing and they could not handle the problem. The miss is pronounced but seems to get better after the car has been running for 15 minutes or so. Any ideas what the problem might be – the mechanic confirmed it was not the fuel lines or fuel filter.

Did he give you any more definitive information?

A “Miss” could mean anything from a misfiring sparkplug (the usual meaning) to a random misfire caused, for example, by a flakey igniter, to a sticky tappet that’s causing a compression irregularity. I’m having a hard time envisioning a mechanic tyhat couldn’t handle an ignition misfire so I’m wondering exactly what symptom he was describing. The comment about the fuel lines makes me wonder if he was alluding to a misfiring injector (is this a throttle body injected system as I suspect?).

Can you be any more specific? And what was the reason he gave for not being able to handle it?

Has anyone checked to see if there is a stored error code in the computer?  Some auto part stores (like Autozone and Advanced Auto Parts) will check for free.  If so get the exact code like P0123 as well as the English translation and post the results here.

Joe, this vehicle has the OBDI engine management system. So the codes won’t be the P0XXX variety. Instead the codes will be two or three digits.