Heres the problem, My truck starts and runs rough and really has less than normal power until around 3000 then feels fine. I have true dual exhaust and am getting a little smoke on cold start up from the driver side pipe.After warming up the engine will surge at a stoplight, going from around 600 down to 300 and sometimes dying, but other times catching up and doing it again. When driving around at low rpm the engine has a pretty bad shake, but will run perfect in the upper rpm range. I am thinking maybe its the injectors(187,000 miles). The engine ran fine for about 4500 miles then started this crap!

Little background on the truck:

1994 half ton tbi 350/ 4l60e auto.
around 5500 miles on new engine.
zz4 cam, holley 300-66 intake, stock heads
comp cams magnum 1.6 rockers

things replaced:
plugs
wires
map sensor
adjusted timing
coolant sensor
fp regulator
pcv
checked for vacuum leaks
replaced some vacuum lines
fuel pump
fuel filter
Adjusted valves several times and also adjusted by veteran mechanic.

Things next on list(lack of Funds)
02 sensor
Tps sensor
cap/rotor
coil
Injectors, (yikes)
knock sensor
IAC


Please help, I'm about to drive this crap off into the lake!!!!

 

It would be good to get some bigger and newer injectors. That could definitely help. Have you advanced the timing at all on this engine?

 

Same exact problem I had turned out to be a bad EGR was dumping exhaust into the intake at idle.

 

timing is on 8 degrees advanced right now, EGR has a block off so thats not it. Thanks for the suggestions guys!!

 

What kind of smoke, what color, and how long till it goes away?

If your fuel system is fine, (sounds like you replaced most of it). Then the only thing I couls see (thinking and thinking) Is possibly spark? perhaps the cap and rotor?

Maybe spray some water (light water) on the plug wires and lisen for the arc, or do it at night. Seen bad wires out of the box.

Let me know about the smoke

 

I think its fuel smoke, light grey its kinda hard to tell(dumps).
I'm going to put a cap and rotor on it today, we'll see how that works.

 

Could the smoke be condesation or is it everytime you start it?

I could have my colors wrong but I think black smoke is fuel..

 

I could have my colors wrong but I think black smoke is fuel.. [/B][/QUOTE] yes.

 

it could be black, its dark under there!

I know it smells really rich(unburned) and it will do it every time you start it until it warms up. I pulled the old cap and the inside terminals are black with corrosion, I bought a new one today after work and I'm going to put it on this afternoon. Hope it works.

 

well, the cap and rotor helped smooth out the idle, but it still has a misire and is still blowing a little smoke.

Maybe the plugs are shot after running rich for so long.

 

If you are having a misfire or a rough idle like that it sounds like your distributor is a little off. You need to check your timing again. If you have a timing gun, this makes it easy. When I put my 350 in, we accidently put the distributor 180* off, and when we fixed it we were way off 0*. The timing gun made it simple to find tdc and then advance it from there.

 

My plugs fouled in about 2 days, I ran the fuel pressure up too high and it was a while before I had time to work on it again.. also cost me about $50 in gas