[Phillip]

I checked the manifold reading with another app (Dash Command) and it turns out that this engine doesn’t have a built in vacuum gauge. It estimates the vacuum from other sensor readings, so probably isn’t that accurate.

I tried the ODB2 adaptor on my mum’s 2000 RAV4 but strangely it couldn’t obtain data from the ECU.

Thanks for the advice guys. Looks like I’ll need a proper vacuum gauge to diagnose the engine.

[Phillip]

Thanks Bluesnut.

I’ll look more into the exhaust system. I guess it’s possible that there’s a partial clog that’s not bad enough to show a different vacuum reading with ETCG’s exhaust test, but would still cause a drop in MPG. It looks like I’ll need to stick a pressure gauge into the Air/Fuel sensor port to properly test for back up pressure.

I also just remembered that my mother drives a Rav4 with VVTi so I’ll test how the manifold readings go with that car for comparison.

[Phillip]

It’s just the manifold readout from the ODB2 port. I don’t really know how it’s measured. Seems to be a built in pressure gauge.

The car doesn’t show any sluggishness. I tried ERTCG’s vacuum test for a clogged exhaust and the reading didn’t change for either 2000 or 3000 rpm, so exhaust is probably ok.

I’m just curious if other Toyota VVTi engines show boost pressure in the manifold when accelerating.

One thing that isn’t within Specifications is the MAF reading at 2,500rpm. Service manual says it should be between 2 to 6 g/sec but mine is 8g/sec at 2,500rpm. At idle it is still within spec at 2.8g/sec, reference range is 1 to 3 g/sec.

I’m suspecting that this higher MAF reading is related to the lower MPG I’m getting. Car reviews say it should get around 23mpg but I’m only getting 18mpg at the moment.

[Author]

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