Hello Everyone.

I have a 1998 Lexus GS 300 w/ 191,000.

I don't know how to exactly describe the problem but here goes.

Check engine light is one w/ p1071 code - too lean condition.

The car idles fine. No stalling. No issues.

The car revs fine w/o issue in park.

When I accelerate, I can accelerate normally as long as I go SLOW.

If I give a lot of gas the car revs for a few seconds, you can hear a POOF sound come from the engine and then it eventually accelerates fast like it's supposed to.

I just changed out spark plugs and changed Valve cover gaskets but this problem existed before that. When I change the spark plugs out, I found them drowned in motor oil. When looking into the holes from where the spark plugs go, a lot of "crud" can be seen.

Anyone have a suggestion or can explain the POOF Sound ??

Much appreciated !

 

I also did replace the MAF sensor but issue still exists...

 

check for vacuum leaks
..

 

I just changed plug WIRES as well.. BIG difference but too early to tell for certain if it's fixed

 

You check your O2 sensors? I believe some people had that code and ended up being that.

 

I also one time changed my spark plugs on my gs430 & started getting a weird mellow popping sound coming from the engine, along with some weird accelarating. But i got a code for a missfire on a certain cylinder, all i did was put a spark plug back in that i previously took out & problem fixed. I know usaid u already had this problem before doing the tune up, but just saying. hope mavy this helped..

 

I've been driving more and more and now... The hesitation is gone when I floor the gas pedal. The poof sound is getting weaker and it is happening less and less often...

Perhaps the caked on oil that seeped in the combustion chamber from those valve gasket is slowly burning off...

Although the poofing sound seems to be coming from close to the driver side firewall or under my feet while driving..

I'll drive it off for a while and see what happens... w/ any luck, I can just drive it off...

I took the car to meineke for free exhaust diagnosis and they said it was good.. to diagnose a drivability issue however starts at $95...

THANKS FOR THE RESPONSES

 

Is there some sort of hose I can check... by drivers side firewall? That seems to be where the poof sound is coming from...

Thanks.

 

I just got back from Lexus and was informed the fuel pump was bad (low pressure)... makes sense but I'll change and we'll see if it does the trick...

They wanted $1,000 to repair 1/3 value of the car !!

Diagnosis was VERY reasonable at only $100 assuming that is the correct diagnosis..

Will report.

 

It's official. Bad Fuel pump! I replaced it myself (was easy) and car is running tip top !

 

I got the replacement on eBay for $100 (the whole assembly not just the pump) and was easier to replace that way as I didn't have to get inside the assembly.

You know your fuel pump is on its last leg if the car drives better on a full tank than when it is running low !!!! I've had that symptom for some time.