Rough idle, sputters

QWERTY123

MEMBER
1997 NISSAN TRUCK
110,000 MILES

I have the truck listed above with a 4 cylinder engine. When I first start it and let it idle will go from 800-900 RPM's down to 300-400 RPM's then back also before it reaches operating temperature while driving will hesitate and bog down. Once it comes up to driving temperature it drives fine no bog down/sputter but still surges at idle. Have just replaced MAF sensor, alternator, and fuel filter.

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

When this is in open loop which is what this is in before it warms up looks at most all sensors except for the o2 sensors. So the fact that it runs well after it starts looking at them, means it is getting bad information from the sensors it is looking at or the ECM is faulty.

So we need to look at the scan tool for what the temp sensors are reading with the engine off and cold. The intake air temp, engine coolant temp and ambient air temp should all be about the same. If one is way off then that is the issue.

Here is a review of a tool that would give us this info:

https://www.youtube.com/watch?v=XY-1CsAzrFA

Also, here is a guide that will talk about some of the other things we need to look at.

https://www.2carpros.com/articles/engine-surges

Lastly we need to use the scan tool to monitor the baro pressure. Just compare this to what it says on the internet for baro pressure in your area.

If the control module is getting all the correct info, then the only thing left would be the control module so we would need to replace that.

Let me know what questions you have. Thanks

Image (Click to make bigger)