• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Popping noises minutes after starting

DharmaDog

NAXJA Forum User
Had a new problem come up today. I started my 98 4.0 up and drove it to campus. No problems at all. But on the way back, after it had been sitting for maybe 2 hours in a very heavy rain it hesitated at a light and made 4 loud popping noises from the engine. I tried to get it to do it again on the way home, but it would not. I stopped at Sam's to pick up some things and then again after it had an opportunity to sit again it hesitated and made more loud popping noises again after coming off a light. Any idea on this? The only recent change I've made is using Sam's gas starting the previous tank.

Another odd problem I've been having intermittently is that if I have less than half a tank of gas and accelerate during a hard left turn, the gas gets cut off for a second and the the engine hesitates badly. I think this might be the fuel filter. I have 80,000 miles exactly as of today. :helpme:
 
Oxygen sensor.

It's supposed to be changed at 80,000 miles. When it dies, it can allow the mix to become too rich, and the result is unburned gas being exhausted and burning when it hits the catalytic converter. That's the pop -- if you've ever heard an older car backfire through the carburetor, that's what I think you're hearing.
 
Last edited:
I replaced the rear O2 sensor about 2 years ago or about 20,000 miles ago. I did not replace the front one. I recently moved to Houston from Austin and no longer have a garage. My lease forbids me from doing any car work, but I imagine that I can quickly swap out the O2 sensor without much problem. However I will not be able to tackle the fuel filter. Approximately, how much does it cost to have it changed?

Thanks.
 
The front O2 sensor is the one that controls the fuel/air ratio. The rear one only checks the function of the catalytic converter.

On a '98 the fuel filter is integral with the fuel pump and is not a periodic maintenance item.
 
Hey Eagle,
Thanks for your help here. I am aware of the difficulty in changing the filter, which is why I cannot do it without a garage to do it in or at least someplace that doesn't forbid me from doing it.

But still, how much can I expect to pay to have it done? How long should a fuel filter and pump last?
 
Hey Eagle,
Nevermind, I figured out what you were trying to get me to understand. I contacted a local service shop and they explained that it does not need to be changed.

So maybe all my hesitation problems (and my poor mileage) are caused by the O2 sensor. I picked one up today and will put it on either tonight or tomorrow morning.
 
OK, I put on the new Bosch O2 sensor and took it for a 10 minute ride. The engine was cold after sitting for at least 3 hours and with the new sensor in it made the same popping noises within a few minutes. I assume that the computer needs to adjust itself for the new sensor and will see what happens tomorrow once it hopefully has a chance to do so.
 
OK, an update:

I changed the oil today. Mobil 1 as always. Added some techron to the gas. Drove around Houston on the highways for ~30 minutes. Tried to blow some crap out of the engine. Runs fine at highway speeds. But still having problems with hesitation after it has been sitting for a while. On the up side, it passed the Houston smog test today. I wasn't expecting it to with this problem. I assume it is running too rich. I got a check engine light today. The codes were 132, 135, 138 and 436 (not real sure about the last one). My understanding is that the 130 codes are regarding the O2 sensor, but which one? The 436 number has something to do with a fuel sensor. I got the codes cleared before I got it smog tested.

The rear O2 sensor is less than 2 years old with about 20000 miles on it. The front one was replaced this week.
 
Anyone have any other ideas or know what would cause the O2 sensor error codes. The codes are back again after replacing the front O2 sensor.
 
Back
Top