mkeef

I have a 1994 ES300. The problem I have is that when the car sits overnight, it has a cold start problem. It will die if I do not hold the gas pedal with RPMs at like 1000-2000 for a minute or 2. Then it runs fine....

Does the 1994 ES300 have a cold start injector? What else could be the problem? Anyone else have this problem?

lexusk8

There are a number of things that can contribute to the cold start problem. I'll list a few I can think of right now:

1) Fuel injector(s) need cleaning. Consider adding fuel injector cleaning fluid (aka Valvoline, Chevron, STP, etc.) into the gas tank.
2) One or more of your spark plugs is burnt out or not creating the spark needed. Go thru your plugs and check them out. Generally, spark plugs should be changed every 60K (or 90K) miles.
3) Throttle body is possibly filled with carbon, fuel vapor and gunk. You will have to take apart all the tubings from the air box to the throttle body, and clean out the TB with carb choke cleaner.
4) MAF (mass air flow) sensor is defective and needs to be replaced.
5) Idle air control valve is sticking or going bad. This part is found inside and underneath the throttle body.
6) Coolant temperature sensor is defective and needs to be replaced.

At this point, you may be thinking, "Where do I start from here?" Well, your best bet is to begin with the easiest step, which is most likely option 1. If that doesn't change the situation, go to step 2. If you're not mechanically inclined, find a local mechanic who can help you out with what you need, or he may offer some suggestions. Hope this helps out

mkeef

Thanks for the reply.

I tried the injector cleaner in the gas take already. It didn't seem to have an effect. I thought it did at first, but it still has the prob. I didn't check the spark plugs because it just had the 90k service, so I figured they replaced the plugs then...I'll have to double check that...

How can I check the MAF, Idle air control valve, and Coolant temperature sensor.

I am pretty mechanically inclined. My wife just got this car from her mother and it's the first car I have delt with with all these electrical sensors etc...

lexusk8

To be honest I myself have never dealt with replacement of the MAF sensor, idle air control valve or the coolant temperature sensor. I am just saying that any of these items could factor in the cause of your cold start idle struggle. I would bring the ES to a good mechanic, or better yet a Toyota dealership and have it properly diagnosed. Do not mention what you think could be the problem; rather, let the technician figure it out under his own power.

Hope this info helps.

mmarshall

lexusk8 made a pretty good list......but here are a couple of other things:
Are you using the correct oil viscosity? Heavy oil will thicken up and cause drag on a cold engine...more so in winter than in summer. Toyota / Lexus generally recommended 10W-30 back in 1994 and 5W-30 today.
Are you using the right fuel octane? If you engine was designed for 87 octane, using 91 or higher could affect a cold start....higher-octane fuels have different vapor pressures, combustion characteristics, and rates of air-fuel mixing than 87 octane does.
Is the fuel filter and the air filter clean and OK?

ckh1272

I have a '93 ES300 and I'm having the same lag problem (and not when it is just cold. Happens from a complete stop). In "D" is when it happens. In "L", it takes off just fine. This is what I have replaced up to this point:
-Oil change
-Transmission fluid change
-new plugs and wires
-new air filter
-new fuel filter
-fuel injector cleaner has been added
-new Throttle position sensor
-new pcv valve

Any clues?? I'm starting to lean to the MAF sensor or the IAC valve. I'm not real sure at this point. I'm just tired of mechanics wasting my money. One was going to charge me $271.00 to replace the TPS, after saying it was bad!! I bought the part from Auto Zone for $126.00 and it took all of 45 seconds to replace!! That did not take care of the problem. Looking for any reasonable solution. Thanks a bunch!!

jet_jockey

in the 94, the computer should kick the engine throttle up to 2k or so while the engine is cold and then slowly decrease back to normal idle speed. If it isn't, then the first thing to check for is engine codes. If you haven't cleaned the throttle body then now is a good time to do it, just get some fuel injector/carb cleaner and spray it out as well as you can. open the butterfly valve and spray in there well. Another thing to do is run seafoam through the top end, this can help with buildup also. The engine does have a cold start injector.