My 98 1.8 manual's infamous "check engine light came on the other day and soon after that the engine started racing up and down, when warm, when I stopped for a stop sign. It also surged when driving it in these rpm ranges, going up to about 2000rpm and then down to 1300 rpm. I took it in and the service manager said that they would install a new engine computer with the upgraded software. It is backordered so I don't have it yet. Does anyone know what the heck this is all about, what the upgraded unit might to for me? Thanks.

If they found anything about the coolant temp sensor, then my guess is thats the problem. There have been at least 3 versions of software on the 97, I do not know about 98's, but I had a problem that sounds like yours. I tried every version of software (more later on that), the dealer did say it sounded like ECU, and I said it was not, cause I have a second ECU and it did the same thing on that ECU. I ended up being right(as always:))and they replaced the coolant temp sensor, and all is well. Do you have a chip?