2005 Corolla - Different Issues Popping Up All At Same Time

[IEdesign]

Hi all, I'm new here and new to Toyota (have owned 2 Subarus, a Honda and a Mazda in the past) having purchased a 2005 XRS in June of last year (2014). So far I really like the car, it's perfect for around town and I gotta say I am almost in love with it. Only thing is it's developed some smaller issues over the last two or so months that right now are just starting to really become constant and I want to figure out what is going on before it leads to something more serious. Here is what it is doing-

-Car stalls sometimes when slowing down, same thing each time. Clutch pedal is on the floor anticipating the downshift, speed is around 15mph and decreasing, and then engine stall. No feeling or sound of engine cut always just the dash lights lighting up and/or the feeling or losing power steering is what alerts me to it. It sounds ridiculous but heading downhill, and especially heading downhill while turning to the right, increases the chances of this happening. Most times this is while I am actually still driving in traffic and not slowing for a traffic light, so I restart the car while it is still rolling with the clutch in and simply complete the shift as it starts back up and all is well (just weird and a little unsettling).

-Accelerator sticks. Not in the open throttle position, but if I have my foot on the gas and let off completely and then put my foot back on the pedal the pedal won't move unless I apply more pressure and then it sort of 'pops' for lack of a better descriptor. It will do this at traffic lights also for example in a fully stopped position, I'll go to drive away and the pedal will be stiff and not give until it breaks free with slightly more weight and then moves freely after that until it does it later down the road. Again it's fine but just weird and unsettling. There will probably be a time when this causes the car to launch into a car in front of me while driving but so far the lack of low end torque in this Corolla means it's pretty tame each time.

-Car stutters and stalls when in first pulling away from a standstill. As if it isn't getting enough gasoline (almost like someone just learning to drive stick and not giving it enough gas for fear of launching), I have gotten used to feathering the clutch and 'double tapping' the gas to get the revs up before I pull away from stop signs and lights because it likes to bog down unless I do. I thought that maybe this car just didn't have any torque at idle and required some sort of more effort to drive it but a few months back I got a chance to drive a regular (1zzfe engine) manual Corolla from the same year and it was effortless. More buttery and very painless to pull away or drive around compared to what I have gotten used to.

-Gas mileage is pretty questionable over the last 6 months. When I first purchased the car it was in another state and I had a 6hr (334 miles) drive to get it back to home base. It made it on one tank of gas despite going through a fair amount of long hills through the Cascades. When I got home and filled the tank I calculated it out and it was 34.6mpg. Now I wouldn't expect this regularly, for the most part I drive in the city and I am only on the freeway for a few moments to hop on and off, but I was expecting around 26mpg city. Typically though it is not at all unusual to fill up at my usual 1/4 tank mark with ~200-210-220 miles (20-22mpg), and I have even seen 19.2mpg recently. I have the 'performance' 2zzge engine and although I do drive spirited and probably hit the lift point once or twice a day (which snaps the car into hard pull near the redline) when getting on the freeway I'm not pedal to the metal racing around in between. I typically cruise around in 4th or 5th gear at 2k-3k rpm.

Any thoughts on what could be causing these or if they are related?

 

[IEdesign]

Just a follow up to the problems above, this XRS has 94k miles right now. I am only the second owner, and it has never been in an accident. The repair history so far is this-

-The dealership I bought the car from is not a Toyota dealership but had replaced the clutch, the spark plugs, tires, and air filter after the original owner traded this vehicle in to them to purchase a new vehicle.

-On the drive home the CEL came on. When I first got the car back home I had it looked at by a Toyota dealership here because it felt like the car had also been pulling to the right while driving it back. I left it over night and they test drove it and agreed that the alignment was off after driving and measuring but they couldn't read the CEL because it wasn't on for them, the code had cleared itself. They were very professional and nice but also made the usual suggestions of changing out all fluids such as power steering, brake, etc because they thought they were bad/old. As well as suggesting they clean out the throttle body, replacing spark plugs, and other general maintenance items to make the car more up to date. All of that naturally would have netted them close to $1,000 so these things I declined because I had just gotten the car and I wanted a chance to settle in and decide for myself one by one (plus take them to my mechanic who is not interested in selling me everything possible and/or a new car). I did have them do the alignment on the same visit and that made a positive difference as it was.

-A few days later the CEL came on again and then later off. This continued here or there for a month or so before I decided to purchase an OBDII reader so I could see what I was up against before blindly taking my car in to my mechanic. The ECU faulted the Idle Air Control valve. Since the car wasn't stalling then (like it does now) and wasn't idling erratically I simply cleared the code because I figured the IAC was operating but it was slightly out of the ECU's parameters and that was causing it to throw the CEL. However after some research I decided I would properly take the throttle body off, clean it out, and clean out the IAC valve at the same time to see if this made a difference (since most people I talked to said it was a good idea to clean the throttle body after so many miles were on the car, although most were just suggesting using a random spray cleaner while the TB was still attached to the engine). I ended up taking the throttle body completely out of the car and into my work area using a bucket and engine detergent and toothbrush to completely clean the tensioner assembly, getting all the gunk out of the inside around the flap, removing the IAC and getting all the gunk out of it as well, and lastly cleaning the MAF upstream with a MAF cleaner before reinstalling all it all back together. I applied a little bit of lithium grease to the spring tensioner of the TB flap and it was freely opening and closing, I also did not touch the preset position screw. After reinstalling this everything worked and no CEL came on, the engine did seem to be rev a little more freely but this could have easily just been my imagination.

-Two days later the CEL returned, same thing IAC. This time the idle was all over the place and in frustration I just purchased a brand new OEM IAC made by Denso and removed the throttle body once again on a day off. With the throttle body off it was easy to replace the IAC with the new unit and put it back together. Crucially though I made two mistakes putting it back together and I wonder if these two mistakes are part of the reason I'm having problems now. For one, I slightly bent the metal throttle body gasket that sits between the TB and the intake manifold. I also cracked the plastic of Throttle Position sensor by accident with the edge of a wrench as I was putting the assembly all back into the car.

-The day that I installed the IAC the car drove but threw more than several codes and they were constant despite any clearing. IAC, Bank 1 lean, etc. I decided not to drive it until I could replace the TP sensor with a new one, which I did the next day from the dealership, again OEM Denso. With that new TP sensor bolted in I took it for a short drive but the codes persisted, and I ended up taking the car to my mechanic and had them diagnose it after I felt like I had messed everything up. They checked the ECU for continuity and ran some tests and double checked the work I had done. It turned out that the metal gasket I had slightly bent which I figured was so tightly bolted into place against the engine it couldn't have mattered, mattered. A lot. The new replacement IAC was fine and it was just that the vacuum of the engine that was sucking air past the flange and confusing the ECU into thinking the IAC must be incorrect. They popped in a replacement gasket, reset the ECU and all has been (almost) well since. No more CELs.


Fast forward a couple of months and here I am now at these problems mentioned in the first post with the history of repairs you see above. About three weeks ago I took out the gas pedal, dissembled it, cleaned it down, reapplied some lithium grease and reinstalled it. I thought that might have been the sticking but it isn't, the pedal arm and spring move very freely outside of the car. At the throttle body itself the spring and flap don't feel like it sticks at all when I move it with my hands, and I don't see any kinks in the throttle cabling or any obvious point of catching.

In terms of stalling out when slowing down when the clutch is in it makes me think the IAC still not operating like it should be. I am uncertain why. Nor do I understand why when the car is heading downhill the chances of it doing this are much higher. There haven't been codes since all the fixes although the car does idle in 3 or 4 different rpms and it doesn't seem to matter if it's cold or hot. As for stalling when trying to pull away from lights I also think there is something strange going on with the air/fuel metering but it's maybe not enough for the computer to trip a CEL.

As for gas mileage, I think these problems are all tied into the lack of efficiency and mileage somehow. I have just recently read that a worn out intake manifold gasket can show all the symptoms I'm facing (poor power, engine burning excessive gas, odd idling, etc.). I think this may be my next step.

Any experiences or suggestions? I feel lost at this point.

Thank you all! Sorry for being so wordy.

 

[Xrs corolla]

Have u figured out the problem with this im having same problem with my 06 xrs but getting alot worse it stalls at every redlight or stop sign unless i tap gas when the idol cuts down ive cleaned idol control. Throttle body. New injectors. New fuel pump. New fuel rail. New mass flow. New coil packs. New vacuum lines. Ported intake manifold. Cold air intake upgrade. Increased injectors size im starting to think ecu.. Crankshaft sensor..cam pos sensor or oil pump... Guessing oil pump because turns cause it too and possible oil pressure drop. Ive noticed slight peck noice started after its heated up seems to be doing it alot more.. Possible cam pos reader showing -15° advance but only code im getting is emissions system secondary air pump stuck open