Hey!

So i recently bought a '92 President with about 40k miles as we speak, so far love the car.

But I’m having an issue when coasting or deceleration where the RPMs would come down at about 1k it would jerk the car & then bounce up to 3-4k and repeatedly as the car comes to a stop, also has a slight weird idle but nothing crazy.

Car does have a gas smell when cold started, then it tends to disappear once it warms up from the exhaust.

So far I’ve cleaned my MAF, throttle body, new air filter, & threw in some foam for the gas tank but not sure where to start.

Only code I have is “A/T Deterioration of Performance” on my dash (in Japanese) but no check engine light. The tranny fluid is filled way past the full line & not the brightest pink color, so I will most likely flush & replace the filter soon.

Has anybody had any issues with this RPM bouncing? I’ve been skimming through the forums but this is a whole new platform for me coming from Lexus.

Any info would be greatly appreciated!! Thanks!

Congratulations and welcome. That wouldn't be the one that was on Facebook marketplace is it? How much did you end up paying if you don't mind me asking?

If you haven't already you should download the full service manual (its available for free on this site) and take a couple of afternoons to familiarize yourself with it. Take the time to flip through some of the diagnostic steps and do some legitimate troubleshooting vs just throwing parts at the car. You will find that the vast majority of your answers will be in that manual, however it does take some time and patience to find what you're looking for.

No1Dad wrote: ↑

Thu Apr 21, 2022 9:46 am

Congratulations and welcome. That wouldn't be the one that was on Facebook marketplace is it? How much did you end up paying if you don't mind me asking?

If you haven't already you should download the full service manual (its available for free on this site) and take a couple of afternoons to familiarize yourself with it. Take the time to flip through some of the diagnostic steps and do some legitimate troubleshooting vs just throwing parts at the car. You will find that the vast majority of your answers will be in that manual, however it does take some time and patience to find what you're looking for.

Hey! If it was a Blueish grey color here in Florida than yes I was able to snag it for honestly a good price ($6500 with about under 40k miles) & so I far love it I know there was a black Presi w/ the chrome package in Jacksonville but he sold it before I could get the cash. But in comparison to my old 430 it’s definitely a different ball game, the gas kinda sucks on it with the 4 speed.

I’ll definitely look into that manual when I get home, I’m currently at work on my phone

to NICO! I would address the transmission overfill first. If that doesn't fix your issue, I'd look in to the MAF. If you can gently tap the black box on the top of the MAF, or wiggle the wires or wiring harness - and notice any change in idle, you have a loose connection. It's common for the connection of the three pins from the connector on the circuit board to have cold solder joints.

Other common issues are a failing fuel pump (it'll sound like a humming noise coming from behind the back seat, especially when the tank is at 1/4 tank or below). The fuel pump control module is also a common problem after the fuel pump ages and starts pulling too much current.

Q451990 wrote: ↑

Thu Apr 21, 2022 2:33 pm

to NICO! I would address the transmission overfill first. If that doesn't fix your issue, I'd look in to the MAF. If you can gently tap the black box on the top of the MAF, or wiggle the wires or wiring harness - and notice any change in idle, you have a loose connection. It's common for the connection of the three pins from the connector on the circuit board to have cold solder joints.

Other common issues are a failing fuel pump (it'll sound like a humming noise coming from behind the back seat, especially when the tank is at 1/4 tank or below). The fuel pump control module is also a common problem after the fuel pump ages and starts pulling too much current.

I’m gonna try & get a new filter/gasket to play it safe, some folks said just to flush it out & not bother doing that just cuz the tranny may be too filled up for whatever reason (it’s actually past the notch in the dip stick which I thought was crazy both when hot & cold) & having only 40k miles it “shouldn’t” be necessary; the fluid is like a off red, not burnt but not cherry red.

I heard about the fuel pump module & a little trick with the pins to give it a consistent 24Volts but I’ll watch out for a humming when I’m at about a 1/4th i haven’t heard anything so far.

Update: I tried the whole Self Diagnostic thing where you turn the key, codes came up & I have 1 guy who translated it for me saying It seems to be telling me about a sensor needing to be replaced and another says a valve

So now I'm curious if this is possibly relating to a sensor on the tranny or something on the throttle body...like a TPS

There are a lot of sensors. What do these codes look like? On the US market they're usually letters.

Sounds like the torque converter or the trans itself,,have you solved the issue? What was it