Hesitation durring acceleration

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Sep 10, 2018 | 11:43 AM

Jasmyn825

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Hesitation durring acceleration

Hey, I have an 89 4Runner. SR5, EFI, 4cyl. It runs great except when I drive it for more than half an hour it starts to hesitate when I put on the gas. First it starts just skipping a little, and then it will start boging down for longer and longer amount of time until it just slowly slows way down. When I put the gas on it sounds like I’m going over a washboard-like a gently bumpy road. When I take the gas of it’s smooth. It’s like it ain’t getting the proper fuel/air. But intermittently and only after being in the road for a while. So when I stop and it’s been running like that and I manually rev it it isn’t smooth.
I replaced the fuel pump and filter, I’ve replaced the spark plugs and wires, and the distributor cap and rotor. Maybe it’s one of the sensors?

help?

Last edited by Jasmyn825; Sep 11, 2018 at 04:45 PM.

Sep 10, 2018 | 07:21 PM

RAD4Runner

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Could be starved of fuel, clogged injectors? That happened to me after Utah trip when I gassed up at unknown stations (could also be the weather conditions that put condensation / rust in gas station reservoir). A few tankfulls of known good gas, with fuel injector cleaner added and problem went away.

Quote:

Originally Posted by Jasmyn825

Move replaced the fuel pump and filter

Sep 10, 2018 | 07:45 PM

snippits

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Do you smell fuel when it's acting up?

Sep 10, 2018 | 07:47 PM

Co_94_PU

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Automatic transmission or manual?

Do you know what ping is and what it sounds like?

Sep 10, 2018 | 08:56 PM

Punchy

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From: 91765

EGR getting stuck open when it heats up?.
Easy test for this is to pull the vacuum hose from the main diaphragm when cold engine, If the problem continues, Then its not EGR.

Sep 11, 2018 | 05:00 AM

Jasmyn825

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Quote:

Originally Posted by snippits

Do you smell fuel when it's acting up?

no smell of fuel

Sep 11, 2018 | 09:50 AM

Jasmyn825

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Quote:

Originally Posted by Co_94_PU

Automatic transmission or manual?

Do you know what ping is and what it sounds like?

it’s a manual, and yeah, it doesn’t ping

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Sep 11, 2018 | 09:52 AM

Jasmyn825

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Quote:

Originally Posted by RAD4Runner

Figured it out! The last owners did a ˟˟˟˟ty job of wiring the fuel injectors and the connection was slipping, causing it to run on three cylinders from time to time.

running like a dream again, and all the better for all the other work done.

Sep 11, 2018 | 10:14 AM

Co_94_PU

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From: Colorado

Quote:

Originally Posted by Jasmyn825

it’s a manual, and yeah, it doesn’t ping

This is a batch fired injector scheme, not firing one injector and still firing ignition. Without a doubt lean, ping.

Glad you found the root issue before it tore itself apart.