Toyota 4Runner Smog Test Abort Unable to Keep Steady Speed

Just took my 1995 Toyota 4Runner in today for smog test. I let it idle to warm up then drove it for 15 minutes before I went to the smog station. I was watching the smog tech and the test starts, the truck shifts then lurches as the tech gives it more throttle and then the smog machine aborts the test. The technician complained that it won't maintain 15mph. After leaving I drive it 2 blocks at 15 mph, plus or minus 1 mph. It drives fine, no lugging. The ignition timing is on spec. I checked TPS last month for unrelated issue. The transmission shifts according to FSM tables. I've had this Toyota 4Runner smogged 3 times and never had this issue. It has factory tire size and trans gearing. If i convert to a manual valve body is the tech going to know how to use it? It's bad enough explaining the ECT power and overdrove off light to the shop techs.

Answer:

We don't recommend installing a manual valve body on your Toyota 4Runner. The smog check program requires smog technicians' drive vehicles being inspected on the dynamometer while the transmission is in Drive gear (for automatic of course).

As far as the stalling during the smog test... we can only offer you information regarding how the dyno portion of the smog test functions; during 15mph 50% load is placed on the engine, during 25mph 25% load is placed on the engine. Ordinary street driving places less load on the engine then during the smog test. It's possible your Toyota 4Runner's transmission has a defective valve body. Repair/replace with a standard valve body only.

posted by SmogTips Support