Ok, Replaced Spider Fuel Injector but now idle issue, details inside

second sentence correction: "regulator was leaking"

P0306 single P0300 Multiple Cylinder Misfire Detected

P0507 Idle Speed High

P0102 - Mass Air Flow (MAF) Circuit Low Input

Yeah, the p0300 and 306 are handled and no longer are showing up. Just the other two and I've done a number of things. Was hoping maybe for a sequence of replacing things and/or advice on what to check next. Or double check.

quite surprised they did not go with a TBI (throttle body injection) and elected to have a fuel rail with pulse activated injectors~ if your fuel pressure regulator is okay? we should be alright~

http://www.summitracing.com/search/product-line/summit-racing-vacuum- hose

these vacuum hoses will leak, you can see how much by placing an unlit propane torch where you suspect a leak may be happening~

Ok, cleaned the MAF with sensor cleaner. It appears to be getting 10v dc at the plug in (tested with my electrical reader). Also, swapped out the MAP sensor with a friends, same idle issues. Onto the next idea.

well hold on there, the fact that 10v are happenin' ain't really tellin' us nothing- this one uses rare metals to measure very small galvonic variations...computer knows if it isn't going subtle enough and makes with the CEL~

Damned computers. Why does it always have to be so convoluted?

Such is the way with computers. That said, I swapped out the IAC valve with my friends GM 4.3 Vortec and no change. May swap out the MAF sensor next.

try swapping mass air flow sensor with a know good one could aslo try unpluging maf and taking it for a drive a P0101 will likely set but the other symptoms may go away, worth a try

hate to beat the turkey with a stick, but has the ground terminal and connection to ground and to engine been established to be able to take on the 300 CCA needed for starting without getting too hot and smoking? also the positive full of 'blue afro'? isn't a new battery due based on the life, say a 2006 is ripe for exchange for example~

I did swap the mass air flow with a good one. The codes shut off for a bit, though the idle issue remained the same. Then the same codes came back on. I'll be checking various electrical tomorrow. @judge, still trying to understand your last message.

Alright, verified getting 11.40-11.50 volts to the MAF, ground checked and it seems to be doing it's job. Tested the MAF while accelerating in hertz mode steady, no jumps or erratic behavior, seems to follow acceleration and deceleration. MAF had been cleaned with MAF sensor cleaner prior (and swapped out). So I am marking the MAF off. Backing up, I just replaced the Spider Fuel Injector which consisted of removing various sensor power plugs off the plenum and around the engine to get to the spider. I've done the carbchoke cleaner spray test while the vehicle was on looking for a change in rpms (vacuum leaks). Nothing. Now, assuming that my P0300 and 306 code went away (and has not returned) since replacing the spider that the spider is indeed working and that a faulty unit would not create a P0102 or p0507 right?

Hey, I had this happen before on my 96 Jimmy. I didnt get the back of the intake plenum seated all the way. Low input may not be a fault in wiring but the fact there is low input. Check all the intake plenum for opens after the MAF. Maybe the IAC isnt working?

Yes, Jim, I've check that entire MAF from the air box back to the throttle body. It's in good condition, no cracks or anything, it's pretty tight. I did a test I found over at easydiagnostics on the MAF sensor itself and tested it. Everything checks out according to the test. @Andrew, I swapped the IAC out with another and the same result so either my friends is also bad or that isn't the problem. It's too much of a coincidence that the IAC goes out when I reinstall everything. The more likely culprit is as you say, something not sealing on the plenum. I will take this all apart tomorrow and double check that my plenum gasket didn't fold or something when I put it back on. That said, if I take the plenum off, do I need to install a new gasket? And to double check, I don't need to add any silicone gasket sealer to the plenum right? It fits rather nicely into the plenum and the directions didn't indicate either way. What baffles me though is that the idle would be stable at 1300 when sitting parked in neutral but then when driving, taking it out of gear around 2k rpms it shoots to 2500 in neutral cruising and then bounces between 1500-2500-1500 ... I thought that such vacuum leak behavior occurred even if the engine was sitting parked in neutral. At least that's what my old Ford F250 did when it had a leak. That's what lead me to believe that a sensor and/or electrical was failed.

no sealer is needed on the plenum. Here's a new thought, your egr may be sticking open. Check it out. If you take it off go get a screened egr gasket for it.

another thought, have you checked the brake booster line for vacuum leaks. Even the booster itself can leak.

I took the egr out and cleaned it with carb spray and a brush on 2 occasions, once before I change the spider and once after in all of this testing. I'll double check the brake booster line BEFORE I rip everything a part.

Yeah so, taking the plenum off I discovered the gasket on the spider unit itself had gotten compromised due to me putting the plenum back on "not perfectly" ... luckily the kit supplied one and the spider itself came with one thus I had 2 and replaced it. That handled the P0102 code. Next I still had idle issues and so rechecked code and still got the 507. So I replaced the IAC valve and double checked electrical to it, sprayed out the seat that the o-ring fits onto/into. And put it back together, reset the ECM. Now the codes are off and the idle issue is handled. The only thing is that the idle in park is still around 1300, a little higher than "normal". But no new codes have come back on. Is there a standard for what the base RPM should be for a 97 S10 4.3 V6 X vin? Otherwise, I'd consider this issue solved!

Just a little follow up ... more data for the hive mind. The high idle of roughly 1300-1400 and dancing of the idle - AFTER replacing the IAC and TPS turned out that when I took the throttle body off (maybe when I replaced the spider originally), one of the rivets fell out. The rivets are on the butterfly plate and restrict air. There is 3 holes in my butterfly plate and two of them were open. I think it's only supposed to be one according to the pics I noticed much later. I put my finger over it and the rpms dropped to normal instantly. I went to the store, bought a $10 rivet gun and some rivets and FIXED the issue. No up and down on the idle when I am driving. No high idle in park/neutral. Voila!

for your lack of understanding...a "blue afro" of corrosion occurs when the positive cable is not touched...ever~ grows an afro of corrosion~ kind of a HA-HA for hair stylists~

as I tried to explain the ground connection is paramount....creates a blue "weld" spark everytime the starter is engaged...okay for the first 50 starts, then a layer of corrosion will occur in the form of a "semiconductor" for the MAIN ground...which is NOT something that the ECU is happy about....varying available amperages and varying voltages...thru this "brown power" connection...that's why so many trouble codes...the ECU is not given solid reliable voltage and steady amperage...what I was geting at is the most basic GROUND connection....1/0 battery cable to chassis connection....wirebrush the lug...wirebrush the chassis to have a full 300 or more electrical connection....also the 1/0 battery cable that connects to the motor block...this one "juices the goose" so to speak (the goose bein' the startermotor)~ also a NEW battery will insure that 12.5 is at the ready for your computer....shame really that they decided it was okay to put a 300 Amp requirement on the same leg as the perhaps 750 mA requirement....some people's kids, I tell ya~

after you get the new battery...and the main ground re-established get one of these code readers...read and RESET THE CODES~ they should be GONE if I've done my homework~