Toyota Previa 2.4 Stalling When Hot

[hostingosc]

my car:

i have a 1990 H reg previa, its the 2.4 petrol, manual and its covered 160,000+ miles.

my problem:

when the car come up to temperature it idles at very low rev's maybe 500rpm, then sometimes fluctuates up and down to the point where it stalls, it seems worse on longer runs, if i have taken it down a dual carrige way at 70 or so, then come down to a stop junction its more likley to stall than a slower run around town.

The cars is not overheating, the temp gauge is around half way up, there is no water loss or any other abnormal symptoms.

do you think this can be fixed with a simple service, new spark plugs and filters etc or is there something else that maybe causing the problem?

any ideas??

[propnut]

There is no simple answer to a question like this. So many things could be causing this but at that mileage I would start with giving the throttle body a really good clean. It gets gummed up with junk from the EGR valve and this in turn affects the operation of the ISCV (Idle Speed Control Valve). Also check for vacuum leaks all the way from the air filter housing to the throttle body and check all other vacuum pipes as well. Check operation of the EGR valve, the PCV valve and of course give it a damn good service. The plugs are only good for 60,000 miles and you haven't mentioned how frequently it hs been serviced.

If some of the things I have mentioned don't make sense to you then you need to buy a workshop manual and start doing some homework.

[hostingosc]

Thanks for you reply.

Ive not had the car for long and it doesn't have much service history for the later part of its life.

The air filter looks quite new and clean so i would imagine its been serviced no too long ago, but what has been done other than that i can not say.

i have just bought a Haynes manual, the US version as i don't think you can get UK Haynes manuals for these and i have also bought a set of spark plugs and filters to do a general service.

how easy is it to work on the engine? i see there is a compartment to get to the top of the engine under the front passenger seat, but that seems to be for checking the oil and little else. can most of it be got to while up on a pair of ramp or do you need to lift the whole car?

there was one other thing i have noticed when driving, you can here a whistling type noise at the front of the car when revving/driving sounds a bit like a supercharger but obviously its not, is that normal?

thanks again.

Nathan.

[propnut]

Actually there was a supercharged version built for the USA market and I believe some of the wide bodied Estimas as well but not in 1990 so I think your whistling is the cause of your cutting out. At the front of the car is the brake vacuum servo. This takes a vacuum feed from the engine which you can see as a thick black pipe under the passenger inspection cover around midpoint on the inlet manifold leading forward into the front of the car. If this is leaking it will cause all sorts of issues including hard braking. Under your front bonnet there is a vacuum diagram that outlines where all the pipes go. Follow this and check all the pipes for leaks.

Under the drivers seat you will find another inspection cover but will require removal of the seat and carpet to get to it. Under this is your plugs. By the way go out and buy the Chilton manual it is far better than the Haynes one but not as logically laid out.