I bought a 1994 4WD S-10 with Tbi. When I first got it the previous owner said it acted like it was running out of gas. I drove it and it ran fine until the second day, it did like he said and my father said he could hear the fuel pump working and the P/O said he had changed it. It really seems to affect the idle when you put it into Park because it idles up and down like it may die. I don't know what to check first. If I give it any more than like 1/3 gas it stops accelerating and makes a weird noise like it might just die. It really sucks when you are trying to drive and can only get to about 30mph before hitting the next light. Another note is when you put it into drive it lurches fairly bad and my neighbor said he thinks thats because it sounds like it may idle high. I have read many of posts and was wondering could it be vacuum lines, O2, MAP, IAC, TPS, or anything else I mentioned. This is the only problem I am having and if I could fix it this Blazer would become a daily driver. Just ask for anything else you would like to know about my Blazer named Jimmy (ironically) Thanks for reading and sorry for ranting...

 

Well, it could be any one of those things you mentioned yes...


However, what we need to know is what the ENGINE LIGHT codes are telling you. You can check this by using the PAPERCLIP METHOD or using a code scanner. Search out the paperclip method by using the search bar at the top of this screen, and then report back to us with the codes you get.

Obviously you have an engine light one with a problem like this, even though you did not mention it.

Taken via google search:

To use the paper clip code reading method on OBD1 vehicles only (will not work with OBD2) locate your cars onboard diagnostics port - usually under the steering wheel, around your left knee. It resembles an old parallel port for computers.
There will be 12 "pins" or holes on this port - a top row of 6 pins and a bottom row of 6 pins. The upper right hand hole/pin is called Pin A, directly to the left of this pin (top row, too) is Pin B. You will need to take a paper clip and firmly stick one end of it into Pin A and then take the other end of the paper clip and stick it into Pin B. Make sure each end is in there tightly. This is called jumping or jumpering Pin A and B.
Now turn your cars ignition to on or acc. but do not start the car. Now, you will need to watch your SES light in the dash and it will flash intermittenly to show you the codes. For OBD1 the codes are 2 digits - look in your cars repair manual or consult a technician with what your specific codes may mean for your particular car.
The SES light will represent the codes as flashes with pauses between. Short pause between numbers in the same code and then a long pause between codes. Most cars will repeat a code three times before moving on to the next code. So, for example code 21 would look like this: flash flash, short pause, flash, long pause, and that would be repeated twice more and then move on to the next code if there is one.
Note that code 12 means your cars diagnostic system is operating correctly, and your SES light should flash code 12 when it first starts the diagnostics readout. If you do not get a code 12 your diagnostics system is not operating properly. If all you get is a code 12 then there is nothing that the diagnostic system has to report to you - good news.

So having said that, you are going to get a readout like this when you turn the key forward to acc...

FLASH - FLASH FLASH ----- FLASH - FLASH FLASH ----- FLASH - FLASH FLASH ----- (12-12-12) - System ready to report

FLASH - FLASH FLASH FLASH -----FLASH - FLASH FLASH FLASH -----FLASH - FLASH FLASH FLASH ----- (13-13-13) code 13

FLASH - FLASH - FLASH --- FLASH - FLASH ------FLASH - FLASH - FLASH --- FLASH - FLASH ------FLASH - FLASH - FLASH --- FLASH - FLASH ------ (32-32-32) code 32

I hope that helps, you would be reporting to us all that you are getting codes 13, and 32 in this case, and we will be a TONNE of help when we know these codes.

 

Did TBI still have OBD1 in '94?

 

Yep up until 95. Most foreign makes are changed in 94 (why Honda changed most of their line up in 94)

But for the codes check here like what ohsofly said.

http://www.troublecodes.net/GM/

go to 93-95 4.3L "W" vin (check your vin for a "W" or "Z")

 

Yeah, but GM had that OBD1/OBD2 hybrid in 1994-95. My 1995 Silhouette has it.

 

1995 Blazers were vortec though... AFAIK all tbis were obd1 - by obdII it was all vortecs...

 

I did the paper clip thing and it came up with a 22 so I changed the TP sensor and it fixed the lurching and ran awesome for a little while but while driving around the block it just died completely. Also the check engine light is still on and it keeps coming up with 22. Also I noticed the more I drove it the worse the "running out of gas" effect occurred, If I turned it off and started it up again it was better for a little while. Oh and I saw that when I put it in Park it still idles up and down and the oil pressure gauge dipped up and down pretty bad but only once and in sync with the idle? What does that sound like? Low oil, I checked it and it could use a little bit but it is above the add oil on the dip stick... Sorry to rant again and add so much into this one post. Anyways thanks guys for actually caring to help.

 

Here's another thing about which to speculate: ignition control module. At the very least you can pull it out from under the distributor and take it to your local auto parts store and have them test it. Be sure they test it at least four times to make sure it's good and warm since that's when they tend to have problems.

 

When you took out the dipstick did you smell gas in the oil??? Mine did that when it needed injectors. But that is normal the higher the rev especially if its cold, its compensating for the revs so that the engine isnt worn down. But what is the gas mileage?? should be near at least 14mpg. another sign for injectors. I dont know how to do it but most would recommend getting a fuel pressure tester and see if it has the proper pressure or if it is leaking.

 

I had the ICM tested and it was fine ;however, a friend of my dads told him a common problem with cars is that they get a thing called air lock and just lossening the gas cap a little may fix it. I dunno but has anyone heard of such a thing. By the way I do not smell gas in the oil. It still runs pretty ehh, except the lurching is better like posted above. Any more things I should/could check first that is easiest/cheapest?