A moment while I rant- *&&(%@#R$()*^. Ok, (1998 4wd) so after everything I have replaced and thought the issue was fixed it came back this morning with a vengeance. Pull out of comfy garage, leave it running a few mins while I run inside to grab phone and such, beautiful sunny morn but cool at like 39f. Going to local stores, few grocery’s to get. 6 blocks up street first stop light, wait to turn right on red and engine stalls out. Grr, slap in neutral and restarts and off I go. Cross over interstate to next red light and stalls again. What? Restarts right away no problem. Next light is for W-mart. Red, I put in neutral this time before stopping and it still conks out. Grrrrr. Restart again without issue. HIt my spot to buy a carton of smokes and leave it running. Stays running fine. Go to next stop- Menards. NO problems. Leave, back to main line road at light to head home and dies again. Catch light otherside of interstate green so make it back no more stopping to driveway and never died. Ok- that’s how it went.

I have replaced idle air valve, TPS, Egr up front. Replaced several vacuum lines all near the cruise control module that I had replaced. Cleaned quite a bit of the whole intake. There are no codes. No security warnings and it always starts right back up. Earlier I was told that the idle is controlled by the ECM but I felt idle is low, currently in gear around 550-570 once warmed up. No problem cold. In park/neutral looking more like 600. This truck has over 200k on it. As is later today replacing fuel pump (Delphi) and strainer (Delphi) and filter when I drop tank to fix the gasket seal which leaks when full. There is a strong gas smell back left rear that I think is a leak in a hose, maybe the evap but no errors for it and will know more once I drop tank. Not sure if this will fix the problem.

All this said, to me seems like the idle is just too low. I did double check that TPS by watching live data on my ODB reader to make sure it was just at the 0% status because I was told that the torx screw on throttle hammer is just to keep the butterfly from closing too far and getting stuck, NOT to bring my idle up and when I try’d that little experiment that idle would not come to rest properly when driving normal and letting off gas pedal. I have not found any more vacuum leaks, tested with a propane touch. How do I raise the idle like 100 rpm then? Is there a magic wand for this cause I could use one. Looking for ideas. I will report back on my end once the fuel tank job is done if issue goes away on rare chance that cures it. Leaving noonish central time to his garage shop to do it (he has way better tools than me).

Quick update..used..go figure. This saves a ton of trouble..
https://cimg1.ibsrv.net/gimg/blazerf...863891753.jpeg
Why don’t mfg just make removable covers for this?

It was nice that someone had already cut that access to the pump and it was already changed over to the newer flat 4 pin connector and new line ends. New pump very quite. Not sure if idle issue fixed yet because not done enough test driving but I have hope. Sealed up opening with a good amount of exterior sealant and some plexiglass I had laying around.


https://cimg5.ibsrv.net/gimg/blazerf...2d137b08f.jpeg

Kinda my thought, should be fairly easy to remove the sealant and plexiglass. Cost wise even if I started over when this covering is removed think still cheaper and easier than say using metal and bending/shaping and sealing. I can see if I missed a spot this way and as you pointed out see inside that area for leaks or other issues.

Took run to bank this afternoon, it a little trip seeing was town we lived in prior and liked bank so never moved account. Call it an hour round trip, idle still seems low to me at low 500’s in gear stopped once warmed up. Rises to about 600 in neutral/park. Cold idle is normal all around. It did not stall out at all so I’m tempted to call it fixed but still very uncomfortable with such a low idle in gear. This truck hardly even creeps forward when you let off brake in gear at this low of an idle so when you do press gas pedal its almost to easy to chirp the tires taking off.

I want to say the idle is steady and not wavering much at all. Is my concern justified? Do these trucks normally idle this low in gear? Keep thinking going to stall and I did not try it under load with things like lights on and blower going. No one has said if this is the normal range nor if there is a way to raise it say 100rpm. Real interested in some of your trucks, do they idle this low or even lower?

Boy that was a long read. I will see what I can do to get those type of readings noting that most of the testing was via android device and I use a iPhone 8 Plus and my current scan tool is a simple standalone device, not bluetooth. Will that adaptor on IOS be able to get you the information you need?

Oh, the fuel pump was replaced not because it was faulty, it pressure tested fine. I replaced it because the seal between the pump and tank was leaking when you filled the tank and I did not know prior owner had cut access to it from interior. So according to notes under hood it had almost 100k miles on it and I was replacing seal, dropping tank, I felt replacing before failure a wise precaution along with filter.


https://cimg5.ibsrv.net/gimg/blazerf...a4ad63c2e.jpeg
Prior owner made notes of repairs under hood with paint marker pen, I liked the idea so continued doing it, my notes are in silver.