Car running funny after fuel filter upgrade

[mrpeepers]

Ok did a search and found a response that are very similar to my symptoms.

my car is an s13 with intake i/h/e. The exhaust is shot and i know my O2 sensor and cat is fouled.

After replacing my fuel filter than car ran strong initially and it was very welcome. Now my car is idling worse and my gas mileage is CRAP plus i smell more fuel and experiencing more backfire.

I know the obvious effects of a larger free flowing filter (back fire, more noticable gas smell)

Someone said in the old thread that it could be a bad fuel pressure regulator and the engine could be putting more fuel than it needs to. Is this close?

Someone help!

[98s14inaz]

Yes. Replace the simple stuff first before moving on to injectors etc.

I would swap o2 sensors first because you know they are fouled, then do the fpr, cleaning your mafs out couldn't hurt either.

[masterbunta]

Please make sure you have not created a fuel leak when you changed the filter. The hoses tend to crack as well as leak from the ends if they are not tight enough.

[OldmanPurdy]

You say you upgraded your fuel filter? Did you use a 300zx one or get a new stock one?

[mrpeepers]

The hoses were cracked and replaced them. Rechecked them a few days later, still no leaks.

Upgraded means to 300zx...but im not so sure if its an upgrade at the moment hahaah