What does this pattern related to issue with idle suggest to you?

Similar to a question I've posted recently but have more data now.
'89 Toyota Cressida, 7MGE engine. On cold fire-up it starts great,
will run great all day.
....except if I get it up to running temp then park for say 20 - 30
mins, enough time for a trip into Walmart, then come back out, it
doesn't want to idle. If I get it in gear and get underway, it
generally clears up. By the time I go a few blocks, get to a light,
it's idling fine. Once it gets running right, it's strong. Accels hard
and smooth, no noticeable issues that I can detect. I've noticed this
pattern repeat itself multiple times now - it only recently started
doing this.
Put in a new fuel pump but still exhibiting this behavior.
Any prime suspects come to mind?
Thanks.
Reply to
muzician21
air bypass valve (?) it gets dirty after a lot of miles, then usually the car starts stalling out at stop signs. However you can replace it (low cost), or clean it with carb cleaner. you could have an air leak in a vaccume hose, with car that old, I would replace all of them,
there is an air temp sensor also in the intake manafold, and the sensor in the exaust, they can get weak over time. Cheap to replace.
Reply to
AMeiwes
Just a WAG but my truck did the same thing. Turned out to be a fuel pressure regulator. Not sure if the Cressida has one or not. Mine was vacuum operated and I was told if the vacuum line has fuel in it (which mine did) then replace it. No problems since.
HTH.
Reply to
Derek Henry
Just a WAG but my truck did the same thing. Turned out to be a fuel pressure regulator. Not sure if the Cressida has one or not. Mine was vacuum operated and I was told if the vacuum line has fuel in it (which mine did) then replace it. No problems since. HTH.
Reply to
Derek Henry

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