on my 92 Z28 5 speed it is surging bad at low speeds.before injector change it would do it when cold but only once in a while.was having some injectors going bad so i replaced them all with 24lb injectors.last night driving home,no matter what gear i am in it surges at low speeds.seems to be idling fine at stop lights.once i got home it started to load up when trying to park.about to stall out.once parked it would idle.i can feel all injectors pulsing.do u think the injectors r too much for the 305?or could it be something ignition related going bad.

the car is a stock 305 5 speed.only has underdrive pulleys installed.

 

Did you have the chip updated for the 24# injectors?

 

no i didnt.so i guess thats something i need to read about before i went and did that.i was running out of stock injectors.i guess need to change back to stock ones?

 

No left for work this morning,it started right off the bat.then a few minutes later.it was running fine.few miles down the road it was back.then goes away and didnt come back at all.i am just wondering if it is something electrical breaking down.it just comes and goes when it feels like it.

 

I have no idea what size injectors came stock in a 305, but I doubt they were anything larger than a 19 #/HR. The 275HP LT1's in 93 only got 22# injectors, and the 24's were use in the 275/285HP F-Body LT1's and the 325HP Corvette LT1's. You could be running so rich that its washing down the cylinder walls, risking ring damage, and diluting the oil with fuel, risking bearing damage.

You may be forcing the O2 sensor to work overtime, and the PCM is pulling down the long term fuel corrections, trying to reduce the over-rich mixture. The long term corrections can't pull enough fuel, so its relying on the short term (temporary) corrections to try and lean it out. Srep on the throttle, and you're pouring 26% extra fuel into the engine.

You can't change the injector size without having a new chip burned.

 

well i guess i need to find a good use set from a pick it and pull yard.it is loading up at times.sometimes it wants to die at lights.now i wish i would have did a search before changing them but i was out of factory spare ones.

 

Just buy new. Parts from a junk yard won't necessarily be any better than what you have. New injectors aren't that expensive.

 

yes i know what ur say but done have the funds to buy new right now.plus i have been checking the resistance on the injectors and thats where i have found the bad ones.they should be reading 0.16 but i had one only at 0.04.one was at 0.00 but after tapping on it,it went back to 0.16.i know it must had junk in it and once i did that it broke free.dont help when the car sat for almost a year.