1991 chevy 1500 5.7 tbi erratic idle

[tpulliam79]

well after a few days of driving, problem is still gone.. it searches a little bit at idle in gear but nothing like before, truck doesnt act like it wants to die anymore, well at least I know every sensor and all secondary ignition should be good for a while as they are all new in the last year.

[layn6015]

If you are still looking for a shop I took my 94 sierra to wholesale motors in the valley and they put a crankshaft kit and timing chain in it,and did a good, affordable job. I usually do my own work, but this was out of my league. I live on the west side of spokane

[Jasper911]

Still fighting mine. Swapped my tbi with a known to be good one and the truck is bout the same. I'm tired of this s--t.

Does the neutral switch really make any difference? Or the PRNDL adjustment? The neutral switch might be the only electric part I haven't changed!

[tpulliam79]

alright back at it again , the truck runs fantastic when in park or driving down the road, but when I put it in reverse or drive ( worse in reverse) from park it almost dies then revs back up? all sensors are new and I mean all any ideas?

[NEUMANNZZ]

check voltage at coil, ignition on, engine stopped and in park.
should be 12vdc. put it in reverse. any spikes or drop in voltage. same for drive. might just be the park/neutral switch. does it start in neutral?

maybe cycle the tilt steering in different positions, might help.

[tpulliam79]

i will check the voltage today and see if it starts in neutral , I replaced the switch about 2 months ago.i just changed the coolant temp sensor and thermostat with the proper ones and now the truck gets up to temp but still tries to die when put into gear, I also changed the plugs and gapped them to spec , and it got worse?

[214tattooguy]

check that saftey switch again my was doing that and i just had to get it adjusted better. and fixed my reverse lights too. they come on when i have the needle on the R.

[The_Ogre25]

I know you have already cleaned the IAC, but did you just spay it or did you clean it off and swab out the passage. I sprayed mine out twice searching for the fix for a bad idle. Finally pulled it out and wiped off the IAC pintle gently until it was spotless and then used q-tips and carb cleaner to clean the IAC passage until the swabs cam out clean and the passage was clean.

[tpulliam79]

Originally Posted by The_Ogre25

I know you have already cleaned the IAC, but did you just spay it or did you clean it off and swab out the passage. I sprayed mine out twice searching for the fix for a bad idle. Finally pulled it out and wiped off the IAC pintle gently until it was spotless and then used q-tips and carb cleaner to clean the IAC passage until the swabs cam out clean and the passage was clean.

I have put a new one in and had the intake off multiple times and cleaned all the passages. i will try to re adjust the safety switch, and go from there. the truck runs great except for the blip at idle and when shifting into gear after warmed up. if it werent for emissions I wouldnt even bother

[BigBody90]

Am I hearing this right. Having a bad or non working safety neutral switch causes a bad idle?

[tpulliam79]

also I know tbi injectors click but should I be able to hear them clearly from inside the truck while driving? I have the factory air box and I can hear them get louder as I speed up?

[NEUMANNZZ]

Originally Posted by tpulliam79

also I know tbi injectors click but should I be able to hear them clearly from inside the truck while driving? I have the factory air box and I can hear them get louder as I speed up?

they are pretty noisy, especially if your using an open element filter.

[tpulliam79]

not an open element just the factory setup, so this loud of a tick is ok? it can be heard over my exhaust. and I have checked everything else it is definitely the injectors.

[maddmaxx65]

if you can hear the injectors you need a separator between the supply and return lines - me 94 blazer that i got from the original owner had a crate motor swap and someone left off the line separator and the constant racket drove me nuts - sounded like a fan was running when in fact it was the 2 lines rubbing together - after the separator it quieted down but was still able to hear it - i then split some 3/8 air line and slid over both lines securing them with some zip ties and now all is quiet

[tpulliam79]

i have the separator its definitely the injectors clicking