1994-2002 [Subscribe to Daily Digest] |
It should run faster in the cold! no question about that.
Basics: fuel quality, clean injectors, new plugs... they have to be NKG's. Heat range 6 seems to be the best. Use Techron Concentrate, it can remove some combustion chamber deposits that might be causing problems that the DI and trionic detect. In Canada, get a good quality fuel system cleaner at CTC.
Boost: check the clamps on the pressurized turbo hoses. Check the bypass valve. Is the diaphragm able to hold pressure.
To check the turbo: remove the hose from the wastegate, or the one that goes to the end of the boost control valve. Now drive carefully. You will need to be ready to get off the throttle. Try a 3rd gear run and the boost indicator should go about 40% into the red on the indicator, then you will get a pressure induced fuel cut. With an autobox, I don't know what control over gearing that you have. If you hear knocking, get off the throttle. If you get lots of boost and it runs well up to that point, then the turbo is good, and obviously it is not a gross leak that is limiting pressure. If you don't get lots of pressure, and big time torque then the turbo is bad, very unlikey, or there is a big leak. If you get knocking, then the ECU is limiting boost because of that. If you get lots of power up to the fuel cut, then the fuel pump is delivering properly. Fuel pump delivery problems are usually seen at wide open throttle with torque and boost falling off at higher rpm's, possibly with some knocking, but the tronic might take care of that. This test should be quite brief, then refit the hose,
Find a location with no traffic as you will be driving at unsteady speeds.
Other possibilities... a very dirty air cleaner, or a fouled cat converter, or a shifted baffle in a deteriorating exhaust system.
Remove the grill, inspect the intercooler for damage, cracks etc.
The solenoid valve that controls the boost could be bad.
The fuel filters are good for over 100000 miles. Sometimes a spark plug can have a cracked insulator and otherwise look good.
Come back with results or further info.
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