I have 93 del sol with a gsr engine. basic mods include header cai and exhaust. On start up it runs great but when it warms up it almost sounds like its missing. There is no check engine light or nothing. Help me please!!!

 

check the plugs.
replace plugs,wires,cap, and rotor.

 

Ignitor, coolant temp sensor

 

Could it be a fuel related issue? the wires are new msd wires, i havent checked the plugs but they are fairly new.I checked the injectors and they tested good. The car has 270000kms...is it possible that the fuel pump is on its way out?

 

I think you need to explain the problem a little better. Does the car run great until it gets fully warm then it runs like ****? When you say misfiring does the motor backfire out the exhaust? Or is it a hesitation? Does it have problems just free-reving or only while driving. More info needed!

 

if it was havng fuel problems it most likely wouldnt even run. not just went it gets hot.
my friends nissan did this same thing and i think it ended up being the motor was totaly junk.

the car has 270000kms but how many does the motor have?

 

the engine has around 50kms and it ran great untill last week. It runs like it should when its cold. its smooth no hesitation or anything. When it warms up to 120 or so it sounds like its missing. Free idle and when driving. it does backfire when driving. You know how an engine sounds when you have a spark plug wire off or an injector plug off? Thats how it sounds when it warms up. There were some electrical issues in the car. I believe that i fixed those issues but could a bad ground somewhere cause it to be doing weird stuff?

 

Does anyone have any ideas on this one???

 

If you unplug the primary O2 sensor, does the problem go away?

 

havent tried that...there is only 1 o2 sensor though

 

If unplugging the O2 sensor eliminates the problem, then replace the O2 sensor.