Oh how frustrating! Extremely poor excelleration

[Nismorunner182]

Ok so please read and please help if you could I'm sorry this is long. I'll give you the extensive breakdown.

So, when I bought the car, it had bad hesitation problems. It wouldn't idle above 500 rpm, If I put my foot on the gas it would rev with a very slow throttle response and sometimes dip back down to 500 rpm or die, despite the fact you're pedal to the metal.

Fast forwarding, I replaced the coolant sensor, the MAF and the connector, the IACV connectors and in the end, it made very little difference but I'm glad to get the corroded stuff out of the way.

So in the end, I finally took every ones' advice and replace the spark plugs with the NGKs and viola! It idles ok and is actually derivable. Go effing figure. So then I did an oil change, put premium in it, did oil treatment and fuel treatment too. Idles a lot smoother but the idle fluctuates about 150 rpm or so. So I'll adjust the idle screw, or better yet, get a new IACV and new connectors.

So now here is my new problem,

When I am driving it, (it still runs roughly mind you its a 650$ project car but works at least) the car will accelerate very very slowly. In regular traffic it's ok because of low speed limits, but if I press on the gas and look for a pull, there is none. A prius could out accelerate me.

Also, when I got it back to my house, I parked it and left it idling. I put my hand over where the air filter should be (haven't gotten a new one yet) and the car sputtered and almost died. The thing is, I didn't seal and suffocate it all the way with my hand, I let plenty of air through and it was still wanting to die. Earlier that day I plugged all lose air lines, fix vacuum lines etc, so I am sure all of those are good and tight.

Am I running to rich? That is my suspicion. The ECU only threw a knock sensor code, coolant temp code, and a cam positioning sensor code. The fuel pump is ok because when I fixed the vacuum lines, I also checked my fuel lines. I emptied them, replaced them etc, and re-primed the rails and it fired right up.

I need some solid input. Again I apologize about the length but I want to give you a clear picture. And I know this has been discussed before but this situation is unique I feel

Thanks guys

[rgregoryb]

"300zx hesitation Premier Z" Google it

[rgregoryb]

If you replaced the coolant temp sensor and it is still giving you that code, could be wiring. That will make it run rich because the ecu still thinks the car is cold.

[Nismorunner182]

Yeah that is true, I did use my voltmeter and its reading the correct voltage yet still kicking the code? I still have to reset my ECU right?

[nissanfreak12]

Check for vac leaks and make TPS is adjusted correctly.

Yes, you should reset the ECU.

[DCaff300ZX]

Corrosion will most likely be the CTS issue, plus BOTH sensor connectors need to be replaced because one is the ECU and the other for the gauge in the dash. Corrosion will be an issue with most engine connectors, so a run through them all (PTU and harness, MAF, IACV, CAS, injectors, EGR, knock sensor if TT)) with cleaning of the green crud a valuable job to do and which will show other potential issues such as broken connectors, hoses or leaks, etc.
You definitely need to fix any and all codes that the ECU throws first and foremost, as they all will seriously affect the engine running and even life of your engine.