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Ted Ritter
Ted Ritter, Toyota Master Tech
Category: Toyota
Satisfied Customers: 4447
Experience:  Toyota Master Tech, ASE Certified
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I have a 97 Toyota tercel (manual transmission)with 198,000

Customer Question

I have a 97 Toyota tercel (manual transmission)with 198,000 miles and it was running perfect until a month ago that the car when shifting in all gears start to hesitate after like 2700-2800rpm.Then will no go above 65mph(2800rpm) and will start to hesitate and have to maintain speed below 65mph and the rpm like in 2500.
I already replace fuel pump,fuel filter,spark plugs,spark plug cable,all 4 fuel injectors and just now the catalytic.
And still doing the same.
Submitted: 2 years ago.
Category: Toyota
Expert:  Ted Ritter replied 2 years ago.

Hi, thanks for posting

Does the check engine light stay on while the engine is running?

Does it idle normally, no misfires, no other issues besides the lack of power at about 2800 rpm?

Customer: replied 2 years ago.
No check engine light, it idles perfectly, it only misfires when I take one of the spark plug cable out when in idle but it doesn't misfire..
What I tried this morning was going at 60mph(2650rpm) downshift to 4th gear and the engine instead of going high on rpm it just went down and also the speed up to 40mph when it start to hesitate again and had to put 5th gear again so the engine will be normal.
I know a little bit of car due to my 15 years background as an aircraft mechanic, but this problem has a gremlin in it and don't know what else to do
Expert:  Ted Ritter replied 2 years ago.

Thanks for the reply

It should have a manifold absolute pressure sensor(MAP sensor) mounted on the firewall, it has a single vacuum line connected at the bottom and an electrical connector on it, check to make sure the vacuum hose is not cracked, be sure the wires to the connector are not broken or loose, try another map sensor, without a check engine light on and by what you have already replaced it's my best guess right now.

Customer: replied 2 years ago.
Ok I will try to get a new one..... One thing I have notice is that it doesn't do it when the car is cold, I car run the car cold(not reaching it's normal operating temp) and it doesn't do it that bad, as soon as it reach its normal temp the problem gets worst
Expert:  Ted Ritter replied 2 years ago.

When it's cold the air fuel ratio is on the rich side, when it reaches operating temp the computer leans it out.

Customer: replied 2 years ago.
that can be what?
Expert:  Ted Ritter replied 2 years ago.

It ould be the map sensor, the computer adjusts the mixture based on inputs from it. Another thing that I can think of may be the coolant temperature sensor, if it's out of specs it can send the wrong temperature information to the computer, most sensor malfunctions turn the check engine light on, is the light even turning on when the key is on?

Customer: replied 2 years ago.
the light turns on when the key is on.... I was just wondering about the map sensor because I know a bad sensor at least will bring the check engine light on..... Just for your info the car has always run around 160 degrees but when it on idle it goes to 200 degrees and the fans and thermostat open normaly
Customer: replied 2 years ago.
II can check today the map indications on my obd2 scanner that I have for my phone
Expert:  Ted Ritter replied 2 years ago.

Ok, if it can read live Map date in gm/sec let me know what the results are at idle and at about 2500 rpm.

Short and long tem fuel trim readings would also help,


Customer: replied 2 years ago.
Ok here's at idle....
Expert:  Ted Ritter replied 2 years ago.

Thanks, ***** *****'t see a problem there.

Do you happen to have a vacuum gauge or can you get one? I'm kind of curious what intake manifold vacuum is at idle and higher rpm.

Customer: replied 2 years ago.
I'm going to replace the MAP sensor even I don't have the check engine light on.
The only thing I still find curious is that when the car engine is cold I can run it and go high on rpms and nothing happens, it just run normal.,but as soon it warms up the problem start. What component can it be that when it gets hot start doing this fault? It an enigma to me
Expert:  Ted Ritter replied 2 years ago.

Thanks for the reply, give the map sensor a try and let me know how it went, I'm going to be on a trip today so I won't be able to get back to you for a few hours.

Expert:  Ted Ritter replied 2 years ago.

Hello, just following up since my last reply, did the sensor solve the problem?