Up&Down

So after start up when my truck is cold there is a lack of throttle response while the engine is cold. Once it warms up all is well. Any ideas?

I've done all the typical tune up tasks (plugs, wires, cap, rotor, filters, clean TB, clean MAF)

Thanks.

rworegon

Can you further describe "lack of throttle response"? What speeds, conditions, etc?

Up&Down

Right. Sorry for the lack of detail.

The lack of throttle response is about 15% into the power band. So there is no lag when I'm coming from a dead stop until about 5 or 10 mph (sorry no tach). Then it seems to catch up and be fine.

This only happens when the engine is cold. Other conditions don't matter. If the weather is cold/warm or wet/dry; doesn't matter.

Also note that the throttle on this truck has been a pain since I've had it. See "Vibration while stopped in Drive".

Let me know if there are other details you may need.

Thanks.

chuckd83

Mine does the same thing.

Jomoka

When I first got my '99 4Runner it had both a nasty lag on initial throttle down, as well as hanging revs after the throttle closed. Which is really annoying with a manual trans. You had to press the throttle down about 1/2 second before you wanted power, and take your foot off it about a half second before you were going to shift.

To make a short story even shorter, the previous owner had put an over-oiled K&N filter on it, which had fouled the MAF. It had a CEL that would come and go associated with it. Cleaning the MAF and taking the K&N off cured it completely.

Basically, the hot wire in the MAF had built up a little insulating layer of soot from burning off the K&N oil going by, which was slowing it's reaction to changing air flow. Open the throttle, it wouldn't see it for a half second or so, lean spike and an engine bog. Let up on the throttle and it would keep the fuel going for a second, not realizing air flow had gone down, rich spike which let the revs hang some.

chuckd83

I have a K&N filter so that might explain it.

Up&Down

I don't have a K&N. I cleaned the MAF like 2.5 years ago. Should be fine.

wyoming9

iTrader: (1)

You cleaned your MAF 2.5 years ago??

Just maybe it is time to clean it again?

Then it is your vehicle.