Chevy 350 Help!

[HULK-1]

Hey guys, my DD chevy 3/4 tons motor is running like ****. I went to fill up one day and since then it has been running like ass. It misses real bad, backfires from both the intake and exhaust only at take off. It is extremly sluggish and reaction time is horrible. It also does not want to idle and dies occasionally when driving. The idle also fluctuates from 500 all the way to 1500 rpms. I have changed everything that i could think of that might be causing this problem. I ran all the "bad" gas out of it, changed fuel filter, didnt change the fuel pump cuz it seems to be workin fine and only has 25,000 miles on it. I also changed sparkplugs/wires, O2 sensors, Tp sensor, ignition coil, and new cap and rotor. I am running out of ideas on what could be wrong. My check engine light is fully functional but has not come on. If yall could put in your 2 cents about what u think might be wrong i would greatly appreciate it cuz it has been runnin ****ty like this for a few days now. Fred any ideas? Thanks

Danny

[uglyota]

Is your battery ground tight?
if it is backfiring it should have a "misfire condition" check engine light.
Take it to vatozone and have them pull the codes

[stx4wheeler]

did you adjust the tps when you put it in, to where it reads a certain amount of volts? i know on a ford you are supposed to do this.

Any exhuast leaks?

[J Cooper]

did you adjust the tps when you put it in, to where it reads a certain amount of volts? i know on a ford you are supposed to do this.

Any exhuast leaks?


his style doesnt haven an adjustment

[jerryg79]

there's also, crank and camshaft sensors. Like hippie said, take it to vatozone and let them see what codes it is throwing.

[HULK-1]

i didnt adjust the tps, i dont think on chevys u have to, and i dont believe there are any exhaust leaks.

[CheapJeep]

Check the mass air flow sensor? I know the f.p. is practically brand new (I remember helping put it in) but your description kinda sounds like one going out. It'd be a pita but at least it should be under warranty.

[Seth]

Are you SURE you put the cap on right, it was the right one, wasn't cracked, wires right, etc? what did the old one look like?

[colman]

check the firing order/wires ive gotten them off before (2 backwards and it did that)

[Fredo]

What year is this thing?

edit*
Just saw the signature...nevermind.

I would say either cam position sensor, vaccuum leak and or intake manifold leak at the heads. Also, check to make sure your distributor hold down is tight. Has it been losing coolant lately? Check the oil for water too.

[J Cooper]

check the firing order/wires ive gotten them off before (2 backwards and it did that)


you saying they switched themselves around at the gas station?

[jerryg79]

Hey guys, my DD chevy 3/4 tons motor is running like ****. I went to fill up one day and since then it has been running like ass. It misses real bad, backfires from both the intake and exhaust only at take off. It is extremly sluggish and reaction time is horrible. It also does not want to idle and dies occasionally when driving. The idle also fluctuates from 500 all the way to 1500 rpms. I have changed everything that i could think of that might be causing this problem. I ran all the "bad" gas out of it, changed fuel filter, didnt change the fuel pump cuz it seems to be workin fine and only has 25,000 miles on it. I also changed sparkplugs/wires, O2 sensors, Tp sensor, ignition coil, and new cap and rotor. I am running out of ideas on what could be wrong. My check engine light is fully functional but has not come on. If yall could put in your 2 cents about what u think might be wrong i would greatly appreciate it cuz it has been runnin ****ty like this for a few days now. Fred any ideas? Thanks

Danny

not to be gay, but did you check your oil. I had the same truck with the same thing happening. Its been said on this board tons of times, but the intakes leak. i ignored mine. The coolant leaked into the oil, the gear on the distributor got eaten up and wouldnt hold timing, and of course the motor was toast.

[FJAggie07]

you saying they switched themselves around at the gas station?

Them things have been known to jump right off them plugs and switch around! Like little snakes them boogers are difficult to keep down. I recommend zip-tieing them to your engine block, apparently the heat keeps them relaxed and on their plugs....

[J Cooper]

it could be mexicans

[colman]

you saying they switched themselves around at the gas station?

he did say that he changed the cap, that could have fixed the original problem but putting wires on in the wrong order would have a similar affect and created a new problem. simple mistake... and don't forget about the little engine gremlins they can do all kinds of wierd things when noone is looking

[HULK-1]

i took it to vatozone today and got it scanned. It showed MAF or VAF low input. Jerry, i have checked the oil, its fine, no water. Fred i havent really noticed a big difference in the amount of coolant its been usingand colman all the wires are in the right place and the cap is on correctly, i marked everything. I replaced the mass air flow sensor and its still not running right so all i can think of is a vacuum leak somewhere or the cam sensor, but wouldnt that show up on the scanner if it was faulty? The distributor is also held down tight, im out of ideas on what this could be.

[robertf03]

input low usually means wiring. first clean the connector and make sure its plugged in all the way

[colman]

check for vaccum leaks at the manifold, they corrode. try spraying brake cleaner at the edges and if the idle changes then you have found your leak