Running like garbage

[BSchrowang]

I have a 1993 Geo Tracker ( 2 door, 4wd, 5 speed) and it starts up fine and will run good for a minute then it starts coughing and misfiring. If you turn it off and start it again its fine for another minute. Then it does it again. It has a brand new fuel pump, new plugs, fresh oil change and a clean distributior. Any ideas what it could be? Ive heard it could be an o2?

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[Ridinhi 5,000+ posts]

I have a 1993 Geo Tracker ( 2 door, 4wd, 5 speed) and it starts up fine and will run good for a minute then it starts coughing and misfiring. If you turn it off and start it again its fine for another minute. Then it does it again. It has a brand new fuel pump, new plugs, fresh oil change and a clean distributior. Any ideas what it could be? Ive heard it could be an o2?

You find out what the problem is yet? My first thought would be fuel filter

 

[BSchrowang]

Havent found anything yet, It has gotten slighty worse tho. My engine builder suggested a compression test to see if ive got burned valves or warped compression rings. So its time to make a trip to harbor freight. But im not able to **** with the offroad toy until i get the daily driver back together ( 2010 Crown Vic Police Interceptor). Just waiting to get the heads back from my engine builder...

 

[Papermaker85 5,000+ posts]

sounds like a possible timing problem. does it get better with acceleration?

 

[BSchrowang]

No, if you put the engine under a load ( moving itself ) it starts to stutter and misfire, if you rev the motor at idle its fine.

 

[Bacovish]

Had a similar problem with a dodge pick up. Under load it misfires and no power. At an idle everything was fine. Ended up being the catalytic was clogged. Ended up just punching it out and ran fine. If you can loosen your exhaust before the cat and might get lucky.

Oh...it would also run good at start up and then start misfire. Think it was because the sensor would heat up a little causing the symtoms. I also thought it was a spark problem or fuel problem at first. Unfortunately the cat was the last thing I tried after about 2 weeks of jacking with.

 

[BSchrowang]

I will have to try removing the cat out and seeing if that helps it any, thanks for the input

 

[Bacovish]

Well my father took out the sensor(spark plug looking thing) on the cat so you shouldn't have to remove the whole thing. Removing the sensor let enough air out to diagnose the issue. It still ran rough but enough improvement we knew it was clogged. removing the sensor will trigger an engine light. Fwiw

 

[BSchrowang]

Already have engine lights so its not a worry. Its purely off road so its pretty much always having the check engine light on. Ill try removing the o2 first and see what that tells me

 

[BSchrowang]

Well its not a cat problem, because there is no cat on it..

 

[Bacovish]

Lol. Definitely not.

 

[BSchrowang]

Yea so now im guessing maybe an o2 but im going to pull the fuel pump back out and check it to see if its getting clogged or gummed up

 

[BSchrowang]

Found the problem today! The fuel strainer on the inlet to the fuel pump was getting clogges up by gunk in the tank. So we pulled it and cleaned the strainer and it has no problems! So time to drop the tank and clean it good and we should be in buisness! Trails here i come!

 

[Papermaker85 5,000+ posts]

The filter huh. Yea my old shit brown Olds would run like a champ one day and then like crap the next. Onl y real way to know is check fuel pressure..

 

[BSchrowang]

Only real way to know is check fuel pressure..

Well i had just bought a brand new fuel pump so the pressure should be good, it ran awesome after i put it in the first time