I just got a 96 C/V. with 4.6. It ran great for a week. I changed the spark plugs (91k mi.). and it started going nuts. It starts and dies, starts and dies then starts and runs Ok after the second or third try. It then bogs down under load for a few miles, then runs OK. It then has a hesitation on acceleration. I put in a new fuel pump, filter, Idle motor, and MAF. Could I have put it bad (new AC) plugs? would this cause this problem? Help !! I'm going nutz here>>

 

Did you gap the plugs before installing? Plugs come pre-gaped but they get bumped around during shipping, ect. If you didnt, pull the plugs and check the gap of each one.
Also, check the wires. Make sure that they didnt crack or break loose from the boots when you pulled them to replace the plugs.
Get back to me and let me know what you find!

Wes

 

Well, I changed the plugs again, and gapped them at .055, Checked the wires, they don't look to be very old. I allso changed the temp. sensor, being that the problem is only on a cold start. Still no help. I checked the fuel pressure and found 40 psi idle with vacume and 45 without. This is what the manuel says it should be, but it drops real quick when I shut it off. (I changed out the fuel pressure regulator,and no change). I'm going nuts here (and broke). It don't show any codes on a scanner.
HELP??

 

Turn the key to the on position about 3 times before you try to start. This will allow the pump to pressureize the lines. If it starts and runs then, the pump is leaking off and will need to be replaced. If it makes no difference, look to the Air Idle Contril valve. This controls the idle speeed.

 

I put in a new fuel pump, No change, new idle air valve, still no change. Primeing the fuel pump don't make much differance. I replaced the fuel filter, and pressure regulator too. still no better. I am past $1000, in parts,and labor allready and "no change".