99 - Smooth Idle....but has Serious Hesitation from a standing stop
I have a 99, it idles perfectly in neutral/park. It has amazingly smooth acceleration from 15mph-80mph. 0-15 is the issue, and it is random as well, sometimes it works great but over 50% of the time it "stumbles" a little
I have:
Replaced Plugs
Replaced Wires
Replaced Front O2
Replaced Air filter
Replaced Fuel Filter
Replaced Map Sensor with low mile junkyard pull
Well the problem is that while sitting at a light in drive (automatic) it has this weird idle issue. It kinda chokes a little and you can feel the car shake. From a stop to flooring the gas it will choke a little..stumble and sound as if it is going to stall but it never does. It just "hesitates" I guess. It is like it is running out of fuel or perhaps running too rich. No codes, just the rear o2 code which is common on these, the cat is fine on this car (not clogged), it has great power.
From 30mph and flooring it into 2nd gear from 3rd is perfect, great power, no hesitation. From any other speed even 10mph or 15 and then flooring it from 2nd into first it pulls hard, no hesitation and runs smooth. It is acting like a dirty maf sensor, however this car does not have one. I had a very similar issue on another car and cleaned the MAF sensor and it fixed it. Its acting like its not getting enough fuel or enough air or calculating something incorrectly.
What should I look at next? It only happens under load when more fuel is needed. You can free rev the car in neutral/park and its perfect.
No codes, just the rear o2 code which is common on these, the cat is fine on this car (not clogged), it has great power.
you stated your own problem. most people think the second o2 just monitors the cat, this is partially correct. it can have an effect on fuel trims if it is sending a bad signal to the ecu. like a signal that the engine is running rich. the reason the car runs great past a specific speed is because past those speeds it is a high enough rpm to switch from closed loop to open loop, ignoring the o2 sensor signal and reading from a written map.
i would suggest replacing the rear o2 sensor, clearing the codes and drive it.
My car has done this since I got it as well...Last time my CEL was checked it came up EVAP emission control system or p440 and guage malfunction (my fuel guage only kinda works)
Its really hesitant from 0~15 like you said, or til about 2500rpms and sounds bogged down, then it will pick up and go
i have the same problem and i took it to a specialized mechanic, also a friend, and he said it could probably be the bearings inside the engine itself. about a 400 job (friend rate). ill let you guys know how that turns out. i will also be installing a turbo kit for my corolla so ill be the 2nd corolla in new york with it on. (only seen 1 other one)
i have the same problem and i took it to a specialized mechanic, also a friend, and he said it could probably be the bearings inside the engine itself. about a 400 job (friend rate). ill let you guys know how that turns out. i will also be installing a turbo kit for my corolla so ill be the 2nd corolla in new york with it on. (only seen 1 other one)
ok ill say this once, BEARINGS WILL NOT CAUSE THIS ISSUE. no possible way for them to cause this. even if one bearing shell spun 180* in the rod, it wouldnt cause this. it would cause a shit ton of knocking and your engine exploding from the rod breaking and punching a hole in your engine.
this is a fueling or ignition issue. my bets are on the o2 sensor since he has a CEL and is claiming it to be the rear one. either sensor will alter long term and short term fuel trims when there is a malfunction.
ok ill say this once, BEARINGS WILL NOT CAUSE THIS ISSUE. no possible way for them to cause this. even if one bearing shell spun 180* in the rod, it wouldnt cause this. it would cause a shit ton of knocking and your engine exploding from the rod breaking and punching a hole in your engine.
100% correct - although I'm sure "shit ton" is the not the correct technical term.
It could still be a low compression issue, but most likely fuel or ignition issue as you stated. Start with correcting the codes it has, and go from there.
SSEiYah,
Plug in your scanner and monitor LTFT under normal driving conditions (car warm), if it's way high or way low that will be a good sign of a bad o2 sensor. Also as said before check compression. If you have a chunk of valve missing (as I once did) you would have symptoms like your having.
My car ran great down the highway but misfired like crazy at low RPM's. It misfired at all throttle positions though.
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'98 Prizm 4spd 272K bought @ 221K for $300 Oil consumption fixed @ 265K for $247
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