starting.

[87GMC2WD]

Ive got an 87 r1500 with a 350 TBI. it takes a very long time to start most of the time, while others it starts right away. i re-did my plugs wires, cap, rotor, and fuel filter and it still has the same problem. Anyone have any suggestions?

[VileZambonie]

You mean the engine cranks but doesn't start right away?

Check for spark when that happens and check for fuel pressure.

Fuel pump relay possibly if delayed fuel pressure

It could be this it could be that but give a little more information. Do you hear the fuel pump initialize when you 1st turn the key on and while cranking?

[Lt.Del]

my first thought, timing. 

[87GMC2WD]

its cranking just not starting. but the fuel pump turns right on, its has spark, and getting plenty of fuel. i dont know what else to say. its gotten a little better when i did the plugs and etc along with the fuel filter. i just replaced a gas tank i checked everything on the sending unit. it is a dual tank, but does it on both tanks. what about the timing?

[Lt.Del]

borrow someone's timing light and check your timing.  Or, mark your distributor position then loosen up the distributor hold down clamp (9/16 wrench) and turn the distributor very slightly one way or the other and see if it starts better. Try advancing a tad (turn counter clockwise).  If it rattles when going uphill, back off (retard it a llittle--turn clockwise).

[VileZambonie]

when it does start do you get any black smoke out of the tail pipe? jump the fuel pump test lead at the fuel pump relay to 12v and see if it still starts hard/

[87GMC2WD]

no black smoke. how would i just that lead and where is it? and for the distributer, do i have to take the rotor off? im new to the motor world, im only 16. i know some but i dont have any expeirence with this stuff yet.

[VileZambonie]

find the fuel pump relay and look for a pigtail hanging off of the harness. Use a jumper wire to bring 12 volts to it.

You do not remove the rotor to check the timing, you need to put the EST in bypass mode though.

[87GMC2WD]

what is the EST and how do i put it in bypass mode?

[DnStClr]

EST is electronic spark timing. It means that the ignition timing is controlled electronically, that is, through the ecm (electronic control module) which sends out small voltages to different sensors and receives a feedback from those sensors and then adjusts the ignition timing according to what feedback it gets.  I'm not sure when EST replaced distributor timing, I know it was in the 80s, and it is better system to troubleshoot because you read codes that the ecm throws out. These trouble codes give you a starting point and you can do a heck of a good job troubleshooting using the codes than you can by just replacing this and that and hoping you hit paydirt. Don't ask me how I know...
 Anyhow, keep asking your questions- there's good guys here willing to help. 
BTW, if you look down on the passenger side of the engine, just a couple of inches in front of the stater, you'll see a round sensor going into the side of your engine. That's the knock sensor and it has a wire connected to it. It threads  into the water jacket. You might disconnect the wire and see if your truck runs any better. Not sure that's the problem. But it's one of the sensors that can give you the trouble you have.