Hello - I am a newbie here so this problem may have already been discussed. The engine light comes on on our 94 Previa with 135K miles. The diagnosis indicated that it was an emissions problems, and most likely an EGR valve and/or modulator that is getting gummed up with carbon. It is very difficult to get to those valves to replace them, since it requires lowering the engine ($$$). My questions to all of you who have dealt with this:<br><br>1) Has anyone been able to solve this problem without going to the expence of lowering the engine? (i.e. using a gasoline additive to reduce carbon buildup in the EGR. If so what brand?) <br>2) Are there any special tools that can let you get to the EGR without lowering the engine?<br>3) If you must have the engine lowered, what other parts of the engine should be serviced/replaced at that same time?<br>4) For those of you who have lowered the engine, what was the cost?<br><br>Thanks much! John (Spokane, WA)

I have a 91 Previa and I think it is the same engine. You do not need to lower the engine to remove the EGR valve. All you have to do is to remove the EGR modulator and the vacuum tubings assembly by removing two mounting bolts on top and several small vacuum hoses. Disconnect the exhaust tubing, two coolant hoses, and two mounting nuts on the EGR and it comes straight out