Engine miss worse under load

KEITH297

MEMBER
2004 NISSAN XTERRA
3.3L
6 CYL
4WD
AUTOMATIC
80,000 MILES

Engine miss not real bad on flat, on hill or passing gear real bad it sounds like popping though intake. Did have code for nox sensor with out light on. I have changed plugs, cap and button, nox sensor, fuel filter, and filled with 93 octane. Also, checked compression test. I am now thinking distributor or timing belt.

5 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

If the compression is good, it does not sound like a timing issue or at least anything with base timing (belt). Let me know what the compression readings were. Here is a link to help with finding compression. If the only code you got was for a nox sensor, are you sure it is an engine miss and not an issue with the transmission?

https://www.2carpros.com/articles/how-to-test-engine-compression

Do me a favor, and this is old school, so do not laugh. When it is dark outside, start the engine and open the hood. Mist water on all ignition components to see if there is something sparking.

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Thursday, November 30th, 2017 AT 6:27 PM

KEITH297

MEMBER
3 POSTS

Checked for any sparking. Seen nothing. On the compression test all had 200, except number six. Tried three times, it was at 160, but sounded like tester would not seal. Cleaned o-ring, checked hole all looked good. Still had a popping noise from somewhere. Tried in another hole again an tester fine. Number six is the plug I took out when I change them I dropped and did not find to see what it looked like. Could this be a head gasket leaking under pressure? Also, when starts the popping noise on a pull it looks like something coming out exhaust maybe raw gas. Thank you for your help.

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Friday, December 1st, 2017 AT 3:28 AM

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

Hello,

To me this sounds like you have camshaft that is going flat on one of the exhaust lobes. My guess would be number six. I would remove the valve cover and take a look at the camshaft.

Here is a guide to help you see what you are in for when removing the valve cover:

https://www.2carpros.com/articles/replace-valve-cover-gasket

Also, this guide can help as well it shows what a flat cam looks like.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please let us know what you find.

Cheers, Ken

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Sunday, December 3rd, 2017 AT 1:27 PM

KEITH297