Ok I have looked though alot of posts and Googled the heck out of this issue...
I have a 1989 s10 blazer 4x4 with a 4.3 TBI, Vin Z.
The issue is that it has a really rough idle and is surging in park and when i am stoped in drive, I can drive it but at red lights i have to put it in nuteral. I can smell too much fuel and it is puddeling up in the TB, Also just recently it is grinding when I start it (I think the started is going bad.) and when driving there is a lose in power like some one just flips a switch and says no more then the switch is fliped againg and it goes on down the road. things that have been replaced inclued

MAP Sensor
MAP Sensor Pigtail
TPS Sensor
Injectors
Plugs and Wires
Cat Converter
Fuel Pump
EGR Valve
Engine and Tranny where replaced about 10 years ago and have less the 70,000 on them.

I am loss as to what the issues are caused by but any help is greatly apperciated.

Tonight I took some time to look over things but being that Im not a machinic Im a bit confused, The vacuum hose that goes to the PCV Valve and TB was Wet? The TB vacuum port was full of juck and the pcv valve was nasty too. I cleaned both and still no help with issues. the valve cover is pretty full of stuff too. I was also looking at the EGR Control Solenoid and with the vacuum line that goes to the TB off the engine revs up high but smoother, Could my issue be a bad EGR Soleniod? I will look into the prices and maybe get one first of next week.

 

Check the coolant temperature sensor. If it's reading low it will tell the computer to inject more fuel than is necessary. Also make sure your EGR is nice and clean. Those are the first two things I would check.

 

Sorry I didnt update that I put in a new coolent sensor last night, The one that goes to the computer not the one that goes to the gauge. As far as the EGR I put the new EGR Valve on but should I change the EGR Sensor? Could this issue be the fuel pressure sensor? If so where would I find it?

 

How about the O2 Sensor also controls fuel mixture. Things that come to my mind are IAC, Temp Sensor, O2 Sensor & EGR Valve. Make sure you have no vacumn leaks on the TBI.

 

I went ahead and got a IAC valve and put it in but it didnt help. I took it to the mechanic and the looked at it and told me it was the computer, so I replaced the computer and that didnt even help... looked to see if there are any vacuum leaks and I found one, I used some tape on it to see if it would help but vary little improvment. I am so lost as to what it could be... I have an appointment with a diffrent mechanic this coming teusday... any more ideas I could try? thanks for all the help so far.

 

Check the spark plug wires, there may be arcing, look for cracks or crusted burnt dots on the wire near the end. If the inside of the boot on the plug has no dielectric grease (dry) this will promote arcing around the plug ( this is hard to see at night, use the water test to expand the arc)

 

I was having this same exact issue, I scoured the web for days, this forum and many others, and turned nothing up. I talked to anyone I thought knew S-10's well enough and nothing. Finally I took it to go see some old timer mechanic and as soon as he saw the puddling fuel at the TBI he said you have bad seals. He ordered a TBI Rebuild Kit from Napa and a couple hours later. I was good to go - rough idle. and stalling out at long lights is now gone.

 

95 chevy blazer runs good at high speeds but wants to stall and surgers at idle

 

Still waiting on the Blazer replay

 

Well u might want to try the Ignition switch, Duralast/Ignition Switch (LS442) | 1986 Chevrolet S10 Blazer 4WD 6 Cylinders R 2.8L TBI | AutoZone.com I have a 86 blazer and its located on under the dash on top of steering column on mine. im sure yours is in the same place! you will have to drop your column to get access to it! This part only cost about $15.00 or so! I heard if its bad it can cause alot of problems! good luck and please post your finding, thanks