I am getting poor mileage (10 mpg or so) on 95 GMC 3/4 ton 4WD pick up. It was running a little rough so I changed spark plugs (gap.35) It runs better but still a little rough. Old spark plugs had a white crust over the tip. Inside the air filter cover was a little oily. Don't know if that matters or what it means. What do I have to do to make it run smoother? I don't want to take it to someone because I can live with the roughness if I have too and don't really have the money to repair it. please help
2006-12-14 04:27:13 · 7 answers · asked by Jim7368 3 in Cars & Transportation ➔ Maintenance & Repairs
Check for a vacuum leak, especially to your MAP sensor. I agree to check the cap/rotor for tracking, but a faulty Hg. reading will throw your timing off. Also a new fuel filter wouldn't hurt! '95, does it have the Vortec or the TBI? It's in that crossover period, and the motor's are drastically different.
2006-12-14 04:39:03 · answer #1 · answered by Justin S 2 · 1⤊ 0⤋
You should start with a complete tune up including fuel filter.(plugs,wires,cap,rotor,air filter).I suggest A/C delco OE replacement plugs and buy a distributor cap/rotor with the brass contacts.
A little oily is probably just some blow-by.I would think a 95 would have a decent amount of miles on it and you could have some oil blow-by.Not uncommon.
Also if you have a 95 3/4 ton 4WD with a v8 that gets 10 miles to the gallon you are not doing that bad.I only get about 14 mpg out of my 2wd.
2006-12-14 13:28:57 · answer #2 · answered by Anonymous · 1⤊ 0⤋
Check the gap of the new plugs again. Also don't use BOSCH Platinum plugs, they will make your truck run like a dog. If you are going to use Platinum pay a little more and use the AC/DELCO 100,000 mile original platinum plugs. I had the same problem with a 94 caprice after putting the plugs in, it runs like new. I threw away the BOSCH plugs.
2006-12-14 12:36:40 · answer #3 · answered by Chris C 1 · 0⤊ 0⤋
sounds like you need to adjust the timing, also double check the spark plug wires, air filter change, oil change will help too. also this may sound crazy but it happened on my motorcycle that was running really rough, my battery was bad, i replaced it and no more roughness. also double check the tire pressure if theyre low that to will affect the mileage
2006-12-14 12:43:27 · answer #4 · answered by launchpad 2 · 0⤊ 0⤋
Check your dipstick, sounds like you may have a water leak, it will show up as a milky whitish film on the stick. Check your radiator too, see if there is any oil residue on the surface of the water (vuiewed as a rainbow-like effect in the proper lighting). Also replace your cap, rotor and wires, and check the distruibutor timing (may be slightly off).
2006-12-14 12:37:01 · answer #5 · answered by Compurednek 3 · 1⤊ 0⤋
Jim jim jim.....spark plugs alone do not a tune up make.......try wires and other ignition related parts.
2006-12-14 12:32:23 · answer #6 · answered by Anonymous · 0⤊ 0⤋
You should also change cap, wire, rotor. Should be fine after that.
2006-12-14 12:31:41 · answer #7 · answered by frigon_p 5 · 0⤊ 0⤋