landshrk

I have a '94 4-Runner, V6, 5-speed, 4WD. 200,821 miles. It hesitates, badly, while accelerating, even if it's just the engine revving up. If I put a constantly accelerating rev on it, about half the time it'll rev up smoothly, return to idle (which is sitting at a fairly constant 1050 RPM or so, unless I have the headlights on, where it'll drop to just under 1000 RPM), and then let out a little "whoomp." The other half of the time, it acts as described below.

If I only rev the engine up to around 2500 RPM, or really, any level and let it sit there, it'll sputter and fight, making those hollow "whoomp" sounds the whole time. The sounds are not at regular intervals, but rather, at random.

Once it has warmed up, the engine has a VERY faint, but still perceptible (at least, to me) loping. It's so faint that it doesn't even register on the Tachometer, which is still reading a constant 1000 RPM.

I have a few ideas as to what this might be, but I want to see what the YT Collective Mind has to say about it. Anyone else experienced these problems? Any ideas as to what it might be?

The vehicle has been through a number of owners. The last guy who had it did an entire engine gasket job, and I drove it three hours home, and for many months after with no problem. As far as I know, there have been no major mods to the vehicle. I do know that the EGR valve has been disconnected, but it's been that way since I bought her, and when I reconnect it, it makes the engine run like total crap, loping at idle really bad. There was a fuel leak a while ago, but it's been fixed.

As for what repairs, other than those listed, have been done:
*New plugs, wires, coil, and cap, as of a couple months ago.
*New EGR valve, which is no longer connected to anything.

I read on another thread here that it might possibly be improperly gapped spark plugs, or a leak in either the intake manifold or tubing. I will be checking those tomorrow (as it's dark, and rather cold out right now), and I'll post if anything works. I'll also (probably) be replacing the fuel filter, as that's a typical fix my father used on his old Camry when she ran poorly.

I can't think of any thing else that might help someone answer this. If you need any more info, please PM me, or just post it in this thread, as I'll be checking back frequently. Thanks so much for all your help!

sam333

From your description ( whoomp) your missing( one or more cylinders not firing). Is it missiing at all RPM's hot or cold? Do a tune up first, adjust your valves, check your compression and then fuel pressure.

landshrk

That's what I was thinking as well, which was why I was thinking something in the ignition, and kinda leaning towards poorly gapped sparkplugs. I'll get her tuned up, see where I stand after.