S-Chassis.com - Sputtering between 2500 and 3000 rpms

:wave: OK this is my first post so just let me say hello to everyone. OK now I bought a 240 with no engine off this kid I know from the shop where I was workin at the time. So it was 24 hours away from the scap heap when my masicistic side took over and said "Hey I can handle that!". Well let me just say this I worked 10 hour days 6 days a week and then stayed an average of 4 extra hours a night for about 2 months taring the car apart and putting it back together with the addition of a ka24e I got for 550 bucks from a salvage yard. Given the 150 bucks I spent on the car which already had a brand new obxr exahaust and 16 inch rims I'd say I got a deal. To make a long story short I love this car! Everthing about it is fantasic with the only shortcoming being the 135 hp engine. I really think they should have made that car with at least 200hp. That aside I truely love the car and will never give up on it. Now that you are asleep I am sorry to have to interupt your nap but heres the real question. The guy who owned it had a cold air intake from ingen that he took with him when I bought it. The machanic who removed his engine was a butcher. My machanical experience and my eletrical background really came together to make the puzzle work. Please pay close attention I am listing my questions now and would really like your opinion on all issues. The air temp sensor on the airbox I bought is not hooked up to the wiring harness. Part of the harness where the maf sensor plug is looks like where the air temp sensor would hook up if I were to remove the electrical tape from the harness. I kid I bought the car from told me that the 1989 240 sx doesn't have that feature but he's an idiot. Please tell me this is not true and how I can wire that in. Ok next and related... the care sputters at between 2500 and 3000 rpms. I think and correct me if I'm wrong but I think the EFI is not mixing the fuel right (probably too rich) and is causing this. I know there are like 6 sensors that tell the electronic fuel injection the conditions and how to set the mix. If the air temp sensor is not hooked up this could cause this right. I have heard that improper mix will cause sputtering at high rpms. Also on the bottem of the radiator the hose that comes off has a pipe in line with it with a sensor in it. One wire has broken off at the connector. My engine temp gauge works fine. I think it is the temp sensor for the EFI this would affect the fuel mix too right? I may be totally wrong this is why I'm typing this. Also how can I improve performance. I wanna punch a hole in my cat first off all, I live in Florida there is no inspection. What's the best aftermarket intake pipe I can get that will give me the best gains and what gains can I expect. Also on an unrelated topic one of my valves is rattling on and off. This guy told me that it might be a lifter but does a sohc 2400 even have lifters? I have a whole nother engine in my storage that came with the car. The guy said that the head had just been redone. Not trying to lose you. What can I do to stop that rattle coming from the first valve under the cover? Can I replace that rocker without taking the cam out and redoing the timing and all that. I can do that if that's what it takes but what a pain it will be. I think its just something in the springy thing that is right above that valve and right below that rocker. OK that's it sorry to run on but help me out cause I love my 240 more than any car I have ever owned and I wanna get the most out of it as far as performance and life. And a turbo is just out of the question. Please give as much info as possible. Laterz.:thumb: