well if you read my previous post I am having problems getting a smooth idle, everything sensor and fuel related was replaced except the original multi-tec injectors. I have no codes and no vacume leaks but this thing still refuses to idle smooth. so I figure it has to be cloged injectors right? well everytime someone posts about a rough idle in here, everyone automaticly goes on about tps and iac and things of that nature. which is fine because that is usually the problem but not in my case. So I called street and performance to ask them if they had a clue because they made me my comp. and wire harness. I told him my problem but I did not tell him that I replaced everything. his imeadiate response was...... what injectors do you run???? so i'm automaticly thinking well this sounds good already, because thats the one thing I didn't check. so I told him I have the stock multitecs and he said they are ok but he really don't even bother cleaning them because they just aren't worth it and he would know because these guys are awsome they deal with fuel injection every day, espeacially with tpi. they put them on just about anything. well he said to use a infared thermometer and check every header at about 1-2 inches from the head. fully warmed up they all should read from 240 to 340 (with headers) but each individual header should be very close in temp to the next. well my test conclusion>>>>>>>>>>>>>>>>> no.1 cylinder 308 deg. no3 cylinder 158 deg. after checking only 2 headers I had to go no further. time for new injectors

 

Similar deal for me. Tried a complete tune to get a smooth idle. Mine would really get rough at higher temps, started to feel it missing when cruising at real light throttle. Added FI cleaner and it would help a little at first, after a couple thousand miles it wouldn't help that I could feel. Ready to pull heads and do a valve job, figured the seats were getting rough or the back of the valves was getting carbonned up. Decided to try new injectors after reading so much about the Multecs. Huge difference. Starts, runs, idles better, maybe gas mileage improved too.

 

IAC problems will normally create a condition of unsteady idle, not a rough idle. The difference is that an unsteady idle will be smooth, but vary in RPM. A rough idle is a poorly firing or misfiring cylinder or cylinders.

If you are experiencing a rough idle, you need to make sure the ignition system is reliable. Then you need to test compression or cylinder leakage on all cyliders. Once you've verified that the ignition system is in good order, and the engine is mechanically sound, you can perform a power balance test to help determine if an injector is not flowing properly. Measuring injector solenoid coil resistance is meaningless as an indicator of flow. That will only indicate an injector that may have an electrical failure, not mechanical problems. While the Multec injectors do have a history of suffering electrical failure more often than the Bosch or other Rochester injectors, they also shouldn't be automatically condemned simply because they are Multecs. You need to fully diagnose the situation before reaching any conclusion.

 

yep, everything new and adjusted correctly. everything else checks out. injectors have to be the culprit

 

update!!! my new injectors arived today. dam summit has fast shipping, and I think I put them in, in record time. I just removed the plenum and that was it. took 45 min for the whole job. Wow what a difference. It idles perfectly now and when you tromp it from a dead stop it just anialates the road. didn't feel much different on top end but mid range torque is unbelievable. I must of had some pretty dirty multitecs.:lala: