Alrite guys, I've got a 93 blazer with the CPI Vortec. I've been getting a consistent 8-9 miles per gallon, 11 mpg city and highway. Anyways, first I pulled the intake and the regulator side was a little washed but nothing horrible, but while I had it off I replaced the regulator. Still bad gas mileage. I hooked up our gm scanner at work and did the tests for everything, checked history codes, ect. EGR was operating fine, IAC system was operating fine. MAP sensor voltage low. Replaced and cleared the code, and re scanned a couple days later and that problems fixed. Oxygen sensors are operating fine. Exhaust does not smell rich or anythign(I have no cat). It runs like a raped ape, idles a little rough once in a while right at startup. I ran fuel injector cleaner and seafoamed it. My intake manifold tuning assembley is also new(broke the old one taking it out). My vaccum level is good, fuel filter has been changed less then 5000 miles ago. I always fill up every friday so the fuel level doesn't get down any farther then 1/2 a tank. I can not figure out while my gas mileage is so poor. Any other ideas? My intake air sensor and coolant temp sensor always are operating fine. I popped the Intake manifold tuning assembley again today to check for wash and there is none.
O2 Sensors (bad O2's = bad mpg's) I've gain 3-4 MPG's by changing O2's
Vacuum Leaks
Tighten the carb bolts my always came loose about every 15k (idled bad).
check the air filter and air tubes for blockage.
change the fuilds front and rear diffs
change the transfer case fuilds use the addtives if needed
change transmission fuild and filter.
change oil anf filter (if you have changed oil brands change back to the brand you were getting good MPG's with)
If your do not change your oil make sure it was changed. Quick change oil places are lazy that way.
check the tire pressure.
run the correct size tires (over or under size tires may lower MPG's)
Do not idle the engine (idling waste large amounts of fuel, vortec carb was noted for that)
Do a compression test.
Regap the plugs and change to see if you have the right type (model)
I know its a pain but remove the upper intake and check the platic/rubber lines that run through the intake and to the CPI (I believe its called a nut kit) turn the key and see if fuel mists from any cracks in the hose.
I know its a pain but remove the upper intake and check the platic/rubber lines that run through the intake and to the CPI (I believe its called a nut kit) turn the key and see if fuel mists from any cracks in the hose.
When I had it off for the regulator I checked them and they were fine, this was only about a month or two ago. and intake doesn't show any wash. O well I think this is just normal.... runs like a top... and the o2 sensors are good. I used the gm tech scanner and they were fine.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
S-10 Forum
8.8M posts
183.1K members
Since 2001
S10forum is the community to discuss the S-Series, Chevrolet Colorado and GMC Canyon. Join to discuss rebuilds, modifications, tech articles and more!