i've got a 92 s10 blazer with the 4.3 which when it gets warm it begins to spit and sputter, get crappy mileage and really **** me off. ive cleaned the sensors on the intake, (EGR, Black round thing ect...) and it is still doing it. also the check engine light turns on and off, every time i get it close to a shop it turns off and they say they cant run a codes test until the light stays on. any ideas?

 

Yes, when the light goes on you can get the codes yourself with a paperclip by making a "U" out of it and inserting it into the 5 and 6 pins on your OBD1 port that is down by your knees. This will make your engine light flash the code for you. Just count the flashes. You can find on here if your search the forums on exactly how to do this, I own a reader so I dont use this method.

https://blazerforum.com/forum/showth...ght=obd+jumper this will show you how to do it.

Forget about the shops, we can help you fix it yourself.

 

Checked the codes on my 88 S10 blazer the other day, just need the paperclip and your off

 

the codes read: TPS under .2 volts; MAP sensors say voltage was too low, (high vacuum); or the throttle angle was abouve 21percent while engine speed was at 1200; and the other was about the O2 sensor voltage being too low, then too high. i guess look at the vacuum lines and then the O2 sensor? how would i check that?

 

You can test the TPS sensor ground, +5V supply, and the sensor return. The sensor return should be ~0.5V at closed throttle and ~4.5V at wide open throttle.

Was that the only code or were there others? What were the specific code?

 

13, 22, 23, 34, 43, 44, 45. was a long sequence but 23 i think was cause i had the air box and hose to the intake off. i went through the vacuum lines and found a cracked segment just behind the intake. replaced it. wound up takin the real ERG off and looked at the gasket and found a wash. gunna get a replacement tomorrow night.

 

From the presence of code 23, I can see that you have a CPI engine..

I would say you have something wrong with the circuits for those sensors. The MAP, TPS, and IAT sensor all use the +5V reference from the ECU. If there were a problem with any one of these sensors, it could cause a drop out in the +5V feed from the ECU to all sensors. Disconnect all of the noted sensors and test the +5V and ground wires at each (should be readily apparent when probing the connectors). The last wire will be the sensor return, except in the case of the IAT sensor where the ECU monitors the ground to determine the temperature of the air charge so there will not be a third wire.

Your O2 sensor codes could be from an intermittent ground or possibly be from screwy AFR's caused by the other sensors not functioning properly or functioning intermittently. I would address these codes last.

 

I have also been informed of the intake manifold tuning valve. supposedly theres no code for it. but it wont allow normal airflow above 3000 rpm or 36 percent throttle. sounds about right for what its doin. heres a whole page on it. http://images.search.yahoo.com/image...sigb=12qipto8f

what is the IAT?

 

The MTV just opens up both halves of the upper plenum to air flow from a more direct path from the throttle body to the intake valve. If it fails to move, it could cause lower output from the engine, however, it should not cause an abrupt decrease in power.

IAT == Intake Air Temperature

 

i have a 92 s10 blazer with the 4.3w. i been tryin to find my sputtering problem. in the process i found a corroded cap and worn rotor. after replacing these plus spark plugs and wires i took it around the block. well about half the block and had to coast it back to the house. i have lost all spark in the middle of driving and the damn thing still sputters when i get about quarter throttle. PLEASE HELP!!!!!!!!