1998 Misfires

dpuk44 · Aug 19, 2016

Hi, my 98 Eddie (350k) is misfiring after replacing all coils, plugs and injectors. I also had a replacement O2 sensor and Transmission sensor.

The misfire normally happens after the engine is hot and normally around 40mph or when apply gas fast.

I have been informed that it could be the converter due to it being clogged.

Does anyone have any ideas?

Thanks.

studabaker · Aug 19, 2016

I had misfires and was doing exhaust gasket and found bolts broken. I suspected cat and was told that would send a code. Try to loosen bolts. dont tighten more. check torque specs. Broken bolt is another issue. Mine was in by one thread. I replaced some coil packs at that time. Another problem I had was the connector tab had broken. so if the connection to the coil pack comes off easily then the little retaining tab may be broken and that is part of the wiring harness so.. fixing that is another issue. I put rtv but now its permanently glued on so there maybe a better way. i used locktight at first and that held for a while.

docraymund · Aug 20, 2016

Have an exhaust shop check the converter and check the tailpipe if it emits whitish smoke when the engine is hot. Also check for spark on all cylinders using a spark tester.

dpuk44 · Aug 20, 2016

So today after paying for new injectors (all 8) the car is still sputtering as if gas isn't going through smoothly. I have no ideas and it's making my weekend very sad

Could the speed senor that was put on be the wrong one?
Could there be a blockage in the fuel line? (I use Seafoam)
Could there be a crack somewhere and if so how would I find it? (I'm a novice)
Could it be the belts?

Any ideas would be much appreciated and any tests for this novice to try would be most helpful.

Hope you're all having a better weekend than I am.

docraymund · Aug 21, 2016

You didn't check the fuel pressure. Fuel filter also might be dirty or the fuel pump might be on the way out.

dpuk44 · Aug 22, 2016

Any way to test the fuel pump or fuel pressure? (novice)

studabaker · Aug 28, 2016

When my fuel pump went out it would not start sometimes. Once running mine was fine well i guess it would sputter sometimes on acceleration from a light. Pump is hard to diagnose for a novice and hard to do at home. I had a shop do that. When I ran low on fuel frequently the pump goes dry on turns and stuff. Sounds like that is a good possibility. Take it back to that shop you got the other done.

Jeff55v · Sep 4, 2016

I had symptoms similar to yours with a GM product. I shotgun replaced a list of parts. I finally gave up and took it to a shop. It turned out to be low fuel pressure. They replaced my fuel pump and it ran great again.
I would have never guessed that an electric fuel pump would go bad in the manner mine did. I thought they either work or don't work.
Anyway, food for thought. It's possible your fuel pressure is low, or intermittently low.

1998 Misfires

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