95 Astro Van runs rough

[Braxman]

My Astro van quit running. The problem seemed to be spark related (won't start, smells like flooding). So I changed the plugs, plug wires, and the distributor cap and rotor (both which badly needed changed). Now the van starts fine but idles a little rough and has a slight shudder when driving. The plugs were properly gapped (0.045) and I have doulble checked all the wire connections. Any ides what could be wrong?

[Blue Bowtie]

Welcome Aboard!

Not to dwell on the obvious, but is the firing order correct?

[Braxman]

Yeah. The firing order is correct.

[Blue Bowtie]

Hopefully, you used single side electrode, dual platinum tipped plugs. "Designer" spark plugs, such as the Bosch +4, SplitFire, Accel "U" Groove, and other non-conventional designs can introduce problems. Your plug gap should be correct at 0.045", even though later W engines used 0.060".

The next thing to look into would be fuel delivery. IIRC, teh '95 uses the CPFI system, with the centrally controlled poppet injectors. Fuel presseure is critical on these engines. While soem might argue that the oxygen sensor may be a problem, it should not be contributing to mixture problems on initial startup, since the PCM basically ignores the O² until the engine starts to warm up and the O² becomes active. Test running and standing fuel pressure (after shut down) to make sure the pump/filter are delivering adequate pressure and that the pressure doesn't drop off quickly after shutdown (leaking injector or FPR).

[Braxman]

I wouldn't think it would be fuel delivery since before the day before it refused to start, it run perfectly. The old plugs I pulled out had normal wear, and the gap was a little more that 0.060". Should I try to gap the new plugs at 0.060"?

[isie]

check the egr vale if it builds carbon it will stick open and cause rough idle, very common problem on 4.3 engines. worth a shot.