Engine Very Sluggish When Cold

[markmustangs]

I have a 93 lexus es300 and my car is very sluggish in the morning. It starts up fine, but when I put it in drive and give it gas it is extremely slow. It feels as if I dont even have my foot on the gas when the gas pedal is right to the floor. As it warms up it gradually gets better. My temp gause on the dash seems to work fine. Does anyone have any ideas what could be causing this??? It runs fine when it is warmed up.

[steviej]

there is a 7th fuel injector to help on cold startups. It may be diry or clogged.

Run a bottle of Chevron/with Techron fuel injector cleaner with the next fill up.

A friend had this same complaint and two tank fulls with a bottle of Chev in each cleared it up.

Give it a try, it can only help.

steviej

[SKperformance]

isn't that injector only used for inital start up then shuts off?

if the car is hard to start as in maybe a few attempts before starting

i would say yah

but either way clearing up the system can always help as a cheap and good first step

[piggyncsu]

how long does it take for it to "kick in"?

and i recommend that fuel cleaner..... it kept my car from messing up for a week :) which was a miracle!

[ryanprun]

I have the same problem with a 1993. When the engine is cold it is very slow to respond it usually takes 10 min to get to normal . Any more suggestions would be great.

[steviej]

This problem sounds as if it is engine temp related as you stated.

the only other thing I can think of is a temp. sensor of some kind. 2 come to mind.

1. Engine coolant temp. sensor. The temp of the coolant is used to help in the ECU calculations for fuel management, IAC, spark timing, EGR settings and other emission functions.

2. Manifild Air Temp sensor. The temp of the engine manifold is also used to help in fuel delivery and spark advance.

usually these sensors are pass or fail. They work or don't work. If they fail a code is sent and the CEL will illuminate on the dashboard. It could be that one is not transmitting the proper signal instead of no signal at all, hence no CEL.

You could also have a dealship do a cold startup evaluation.

You have to leave it over night, then they hook it up to many sensors and a scan tool and diagnose what may or may not be there upon start up.

They will look for things like fuel pressure, timing, spark, coolant temp, air temp, etc. This also will cost money to do.

good luck,

steviej.

[SKperformance]

as a thought

most sensors are in open loop when on cold start mode

meaning the computer takes none of the values into consideration when cold

and runs at a set ecu setting

as they are unrelibale readings

usually the car runs better when cold then dies out after when it gets real readings at normal operating temp

[bbsal]

isn't that injector only used for inital start up then shuts off?

if the car is hard to start as in maybe a few attempts before starting

i would say yah

but either way clearing up the system can always help as a cheap and good first step

yes from what ive seen and read its only for startup then shuts down.