Thread: Idle problem / loss of power when warm

Hey guys I'm really stumped here. I have a 96 G20 with a high port 93 engine. Upon building it, all ran just fine. Recently a problem has surfaced and gotten worse. When idling at a stop light, the engine would stumble on occasion and drop about 150 - 200 rpm. (but never die) as of here recently, it's doing it much worse to the point where it does die and sometimes there is just total loss of power so taking off from a light is almost impossible. I checked some of the obvious stuff. Cap, wires, rotor, fuel pressure, plugs but no luck. I took it to my mechanic and he was worthless. He changed the 5 month old cap and wires with no luck whatsoever. He said he suspects the distributor. He thinks when the engine heats up, something is going wrong in the distributor.
Car is throwing no codes or anything like that. Does anyone have any ideas what may cause this to happen once the car has reached operating temp?

Thanks for any help you may have.

Hell no.

first, check for vaccum leaks.

Then proceed with these steps:
Check your tps. I've gone through a TON figuring this very thing out. Make sure it's up to snuff. check that out first on se-r.net's writeup found here:
TPS Voltage Adjustment

Then if that checks out, do this:
MAF Sensor Grounding

Then this (scroll down to egr cleaning):
Problems and Fixes

Then this:
Idle Speed Adjustment

Then read the last few comments on this because mine ended up being a frayed wire!!!:
http://www.sr20-forum.com/general-sr20/18029-strange-constant-speed-issue-2.html#post237768

Don't worry, all these things are very very good to do ANYWAYS to help your car run 100%, so even if you fix the problem on the first or second suggestion, keep going, because they are all good things to do.

Forgot to mention - FSM says that after all this doesn't work - take a screw and plug the fpr vaccum hose - drive. goes away? bam, you got your problem. Doesn't?
Reattach, take screw and plug purge line off canister. fix problem, great. Doesn't? Then continue diagnosis.

.... vacuum

when running cold the ecu compensates an throws more gas ehnce no hesitation or lag problem... when vacuum leak occurs computer freaks.

thanks for all the great info here. I'm going to work on it tonight so Hopefully I will have some good news to report later. What is the FPR Vac hose?

HKS, I wonder if I have an injector that is acting crazy once it gets hot...

I'm in the same boat so I'm going to do a bit of thread jacking as it should pertain to this thread as well.

Ok. I've never monkied with the TPS at all and have NO idea how to read this multimeter thingy either. Its not digital, wish it was. I might just end up going out to get a digital one here soon anyways.

EDIT** Forget this mess. I'm going to get a digital meter.

listen i just remebered this happend to me once...... the strainer on the fuel pump was clogged... check it out its easy to chek it out.... please dooo and let me know

your idle looks around .37. So loosen the tps first and turn it with the voltmeter connected until it reads .45 - .55
wait - ok so from the looks of things, your wot is 4.3V, so turn the screw on the throttle till it reads 4 bang on. Do this AFTER you turn your tps, as your voltage will be adjusted when you adjust the tps. It might very well fix itself.

are you running an oxygen sensor?? if so, is it the original one?? if it is replace it. I had the EXACT same problem with my V-ZR and since if replaced if it runs mint, idles superb and doesnt appear to lose power when its warmed up , hope you fix it soon. Also replacing the fuel filter in the bay will help a little bit, but won't fix this problem, that was my first thing to replace aswell haha

fpr vaccum hose is the hose that comes from a 3 way connector - one hose goes to the egr solenoid, one goes to the vaccum gallary, and the one you want connects to a disc looking thing on the end of your fuel rail.