In colder weather these Corolla's and Matrix vehicle can exhibit a check engine light on with codes P0171, P0300 (P0301,P0302,P0303,P0304) and/or P0133. TSB EG045-07 may pertain to this condition where the intake gasket will need to be replaced with the updated one (part # 17171-22060). If you look at the Freeze Frame data for the P0171 code it could look very similar to the pic below. The LTFT (Long Term Fuel Trim) will be 25% and above. This is because the intake gasket is leaking air into the process and the engine ECU is trying to dump fuel in an effort to bring the fuel air ratio back into correct balance. The next step would be to check and see if the intake has the old or new style gasket installed. The new gasket is orange colored while the factory original is black. Here is where to look... This above shot was taken after the repair and as you can see the small orange colored gasket is showing. Here is how to replace the gasket... Remove the engine cover. Remove the 10mm nut, loosen the 10mm stud nut, and remove the two plastic clips if you have them and remove the engine cover. Remove and set aside the air cleaner and hose. Loosen the 10mm hose clamp for the throttle body and remove the PCV breather hose by pulling it straight off. It should come right off, but if it doesn't press the clamp and lower it on the hose and use hose pliers to twist off the hose. Unclip the air box lid and set the air box with PCV and intake hose to the side. Remove the vacuum and breather hoses from the top of the intake manifold by pulling them straight off. They should come right off, but if they don't press the clamp and lower/raise (depending on perspective) it on the hose and use hose pliers to twist off the hose. Remove the electronic throttle body connector. Push the center connector release and pull off the connector. Remove the throttle body. Remove the 2 10mm nuts and 2 10mm bolts and pull off the throttle body. Route the cooling lines away from the studs and hang the throttle body. Remove the intake manifold wiring harness clip. Using your screwdriver release the catch and remove wiring harness clip from above the alternator. Remove the intake manifold bolts. Remove the bolt the 1 12mm near the bottom of the intake, 2 12mm bolts on the bracket located on the right side of the intake, 2 12mm nuts holding the wiring harness retainers, and 2 remaining 12mm bolts from the intake manifold. Remember where each bolt/nut came from. Remove the wiring harness from the intake manifold by pulling back the two wiring harness retainers (from around the nuts), flipping them around and moving the wiring harness out of the way. Remove the intake manifold by pulling it back and out off the studs. Caution: When removing take note of the hidden vacuum line behind the intake and remove it. Remove the factory intake gasket. Using your brake clean and rag clean the face of the intake manifold and cylinder head. Install the new intake gasket. Make sure the indents line up and seat the gasket flush with the manifold. Install the intake manifold on the cylinder head. Reinstall the two wiring harness retainers around the studs, and on the clip above the alternator. Install all the 12mm bolts and nuts in the proper areas. Don't forget the hidden vacuum line behind the intake manifold from the removal procedure. Be sure to install it now. Install all bolts and nuts hand tight with ratchet but have done around a bunch and never had an issue. Clean the throttle body and reinstall or just reinstall the throttle body by installing the 10mm nuts and bolts. Follow this DIY to clean the throttle body. Make sure you clear the codes and then watch the STFT and LTFT from the live data list. This pic shows a much improved fuel trim condition and a verified repair.
