Engine Hesitation when cold?!

U

Urban

Driver
My car runs fine , seems to have power, but for some reason when the engine is cold and during warm the engine hesitates under moderate acceleration. It almost sounds like a miss fire but other then when it's cold I have no problem. Any ideas would help, fuel pressure seems alittle low(could be the shitty gauge I have), compression is perfect, vacuum is good, and assume spark is fine(cap,rotor,wires,plugs,all new). The plugs are white so it looks like I'm running lean, maybe a lean miss fire for some reason when it's cold because the fuel is pooling in the intake manifold and not atomizing??? I just don't know:confused:. but any help would be appreciated!!! I'm thinking I have a problem but when the engine is cold it is more noticeable.
 
yes, when I bought the car they removed the CTS and rigged an aftermarket gauge where the sensor was supposed to be for the comp. Which made the car run a little rough and run rich.
 
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(KA24DE)For a while now I've had an hesitation problem. I believed it only happen when it was cold but now I have learned that it happens pretty much all the time but is most noticeable when the car is first started. The problem occurs during acceleration at 2000-3000 rpm. I still believe it to be a fuel problem.

It didn't bother me to much until the last time I took it out drifting after finishing (and packing up the car) I restarted the car and I had a large noticeable miss fire. Once I thought the problem had passed (no more miss) I went to leave and it began to miss again (just as bad) and then once it did go away I had a lack of power that then went away after about 2-4 mins.
I'm lost I thought it may be a bad injector leak mixed with a weak fuel pump.
The injectors don't seem to be leaking (bad) when I pulled the fuel rail, and the belief that it's fuel pump should cause more problems at high speed then at low. I just can't figure it out and don't have the money to spend on something if I'm wrong. IF ANYONE has any advice on how to test and check for what problem could be, that would be awesome.

Well I just did all the tests the SM tells me to do with a cold hesitation and normal operation hesitation and found nothing.

New find- I have 30-32 psi (Fuel pressure) but when I pinch the return line the pressure doesn't rise! When I pull the vacuum hose for the regulator again it doesn't rise! This is a new problem that I didn't have before.
And now after removing and pulgging the purge line for the charcoal canister and performing the test the SM tells me to try I have a High idle that won't go away. My idle is also gotten worse(going up and down randomly).

New find- I have a lazy 02 sensor. It doesn't cycle at least 5 times per 10 seconds. FPR is done (dead), No pressure change when I hook a vacuum gauge(new problem). I hope this at least helps fix the problem, I still need a analog ohm meter to check the TSP sensor, that may be the be the problem with the specific rpm hesitation.

New find- TPS is working fine. Atemped to change a FPR with a used one and did nothing = back to testing.
 
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Well well well I finally pull out the pump after leaving me with no other options. The strainer was black. Who knows how long it's been like that. And the tank is clean (yes!). So I'm in the market for a new pump.
 
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