95 Villager: acceleration stumble.

[240FeVeR]

I bought a 95 Villager (same as Nissan Quest). The van has a problem with the engine revving. The idle is a rough, if I open the throttle a slowly it'll rev up but to a limit. If I open the throttle fast it'll bog right down and want to backfire though the intake. The van is unable to be driven in this condition. When I open the throttle it sort of feels like the mass air sensor safe mode but it'll bog down to the point of shutting off.

I read that the engine should run with the mass air sensor disconnected. If I disconnect the mass air sensor the engine shuts off and will not start without it.

What I've done so far:1) Replaced the timing belt (it was due for one anyway). 100% sure it's installed properly. Currently running engine with timing covers off and just alternator belt on to charge battery (short periods of course). Timing belt has not jumped. 2) New battery3) New distributor4) New spark plugs, cap, rotor, fuel filter.5) I bought a new mass air sensor, but that didn't change anything so I returned it.6) Changed the coil and power transistor. 7) New fuel pressure regulator8) One tank new gas 93 octane (being that it sat for a while).

Frankly I don't know how to check the Van's computer for codes. The Factory manual suggests using some connection near the starter which I can't find. I don't have a fuel pressure tester or I would have done it already. Do you guys think it could be the fuel pump putting out low pressure?

Any suggestions are welcome, thank you.

[240FeVeR]

Ok, the problem seems to be timing related. I bought a timing gun this morning and it's way off. Updates to follow.

[240FeVeR]

The timing wasn't as off as I thought. I timed it properly according to the factory service manual and the problem still exists.

I'm really starting to think it's a fuel starvation problem. Auto stores around here don't sell a universal fuel pressure tester, they sell for domestic vehicles with a Schrader valve. Sucks for me. What also makes me think it's a fuel problem is that I allowed fuel to pour into a bowl to see the flow, the flow was allright, but i could stop it with easy if i blocked the line with my finger and it wouldn't be fighting against my finger. When I shut the pump off the line loses pressure and the fuel recedes back to the tank.

[240FeVeR]

Problem solved. It was the fuel pump not putting out enough pressure. I picked up a very clean looking unit at the junk yard and installed it (had to drop the tank argh!) she runs smooth like butter now.