Best cleaner for rough cold idle?

Doubt a "cleaner" will help you. It would be useful if you stated what vehicle you have. I certainly would start with a basic diagnosis including code scanning, fuel pressure check and overall ingnition system condition.
 
Doubt a "cleaner" will help you. It would be useful if you stated what vehicle you have. I certainly would start with a basic diagnosis including code scanning, fuel pressure check and overall ingnition system condition.
2005 Nissan Sentra 2.5l. Owned it since day one...

So it's been going on for a year. P1237 code. I've replaced everything that the code calls for. It's a super generic code....

New fuel pump, bank 1 sensor 1, evap solenoid, coils etc. Runs great and gets good fuel mileage, but at cold idle , it'll act funky. I really don't know what's going on, and yeah a fuel cleaner isn't only going to help cold idle. But I'm at whits end...
 
Like previously stated, check for vacuum leaks.....also do a thorough cleaning of your throttle body. IIRC this Sentra does not have an Idle Air Control Valve and relies solely on the ECM to control idle.
 
Put new Autolite plugs in it and drive on. Daughters Sentra had Bosch Platinum in it. They looked perfect. Read on a board about stumble and put in new Autolite copper and stumble gone.
 
Yo NattyBoh: I'm not on the Scolding Committee but here comes one. Prepare to overreact.
Given the brains and detail you display in post #3, why the vague, sketchy post #1?

I drink the big orange cans whenever I'm in Baltimore!
 
I have checked for vacuum leaks using starter fluid - nothing.

New plus are in there too, oem ones. Might try the cheap copper ones.

I need the light off for emissions.

Throttle body is clean and looks clean...

Bought an oem MAF , same problem.
 
The P1237 code specifies the Fuel Pump Control Module specifically. You never mentioned it.
Was a new FPCM included in the new pump assembly?

If every part is OK try taking the car for a nice, long 4 hour drives. You'd be surprised how much that can help.
Is there a fuel filter (aka the most overlooked filter)?
How many miles on your '05?
Overdose her on Chevron Techron Concentrate (use ~1.5 ounces per gallon of fuel) before a stint of LOCAL DRIVING.
They say the PEA dissolves crud on the injector nozzles upon shut-down.
 
The P1237 code specifies the Fuel Pump Control Module specifically. You never mentioned it.
Was a new FPCM included in the new pump assembly?

If every part is OK try taking the car for a nice, long 4 hour drives. You'd be surprised how much that can help.
Is there a fuel filter (aka the most overlooked filter)?
How many miles on your '05?
Overdose her on Chevron Techron Concentrate (use ~1.5 ounces per gallon of fuel) before a stint of LOCAL DRIVING.
They say the PEA dissolves crud on the injector nozzles upon shut-down.
I did not change that module out... I changed it the complete pump assy. I drive 45 mins a day to work with it. It's my commuter, I'm trying to keep it as long as possible. Lol. I have a new 6.7 diesel on the weekend.

Filter is within the pump itself.

190k miles. Burns about a quart it tad more in 5k miles.

I saw good reviews on the berryman emission pass protection stuff... I'm going to give it a whirl
 
Let me ask you guys this...

Put a tank of 93 in it, the CEL has been out for two days and idles smoother.

And the kicker is that it passed emissions just now.

Does that sound like it needs a combustion chamber cleaner or something? Carbon'd up inside the engine maybe?

Edited: the last few days I kept it at 2500 rpm/65 mph. I left the emissions and drove it at 2950rpm/75 mph and the light came back on. So it's rpm related I'm thinking...
 
Last edited:
Let me ask you guys this...

Put a tank of 93 in it, the CEL has been out for two days and idles smoother.

And the kicker is that it passed emissions just now.

Does that sound like it needs a combustion chamber cleaner or something? Carbon'd up inside the engine maybe?

Edited: the last few days I kept it at 2500 rpm/65 mph. I left the emissions and drove it at 2950rpm/75 mph and the light came back on. So it's rpm related I'm thinking...
I'd put some gumout regane through it with a tank of 93 octane like you did. Inspect oil after the tank as well.
 
Back
Top