I have ap1 year 2000 whenever i start the cold engine it runs fine and smooth, but the problem is when the engine is warm up if i press the gas it seems its surging, i used the OBD2 scanner and found out my ST & FT fueltrim are between -10/-21 running rich, my 02 sensors upstream and downstream are brand new,map sensor,tps sensor,sparkplugs,ignition coil and FPR also are new,i cleaned the TB,IACV, it doesnt have any code thats why its hard to diagnose the problem, please help!

 

That is rich.

is the o-ring under the map sensor in perfect condition?

 

Yes it is, i even recheck everything and reset the ecu but still running rich,next thing i would do if replace the cat converter,

 

mine was faulty tb gasket. A mechanic over the weekend told me the quickest way to find a leak is to use a starter help spray can? spray around the manifold and any vacuum hose. if the RPM goes up. theres a leak!

im not sure if this method is safe. i personally have not done it but as i told my story to the mechanic at a local carx about my car and how i fixed it, thats what he told me to do lol

good luck!

 

i dont think its a vacuum leak because my ST/LT fueltrim are running rich, it means im getting a little air or running too much fuel in it, when i cleaned my TB and IACV i even replaced the TB gasket with a new one also, thanks for the respond by the way.

 

i noticed something weird today, sometimes in Stop and Go Traffic my car stall its like a fuel cut

 

Vac leak will send the trim positive, so thats not it...It's nice to see ONE person using FT to his advantage in 9 years of my posting in UTH

You might have an injector that is hanging up, could even be an ECU. Where you live?

 

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low compression problem


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1st cylinder = 155
2nd " = 145
3rd " = 145
4th " = 160

 

it turns out the ignition coils were bad, so after i changed them with new ones the engine runs smooth again.