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I’ve got a 2000 Chevy Malibu with a 3100 that has a drive ability problem. Vehicle starts and idles fine. I step on the gas 3/4 of the way, no problem. I floor it (wide open throttle) and the engine just bogs down, a complete loss of power pretty much. The tach only reads at about 4000-4200 rpm’s at wide open throttle. When driving and flooring it to pass on the highway I get the same effect as mentioned above. Another issue is when driving occasionally the engine surges and the rpm’s fluctuate a bit, not a lot, but it’s noticeable. Any ideas on where to even start on resolving this or what could be causing these problems?
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Normally, ignition issues show up under heavy load. That’s where I would start. Has the vehicle been tuned up recently/ever? Invest in OEM plugs (AC delcos are like $1 apiece) and quality wires.
Note the GM used a rev limiter that will only allow around 4k RPM in park/neutral.
Ditto on the tune up if not done recently or the last time is unknown. The plug wires are known to rub and arc on the upper intake manifold near the throttle where they usually lay. AC Delco listed plugs are fine but use the proper double platinum/double iridium plugs (NGK makes these and their own line is called Laser Platinum/Iridium) if you are you are going to keep the car more than a year/15k miles. GM DIS systems are very hard on “copper” style plugs.
Check air intake hose between the MAF sensor and the TB for cracks and other damage which would allow air to bypass the MAF sensor. Also check the PCV breather tube from the air intake tube that plugs into the rear valve cover. It tends to pop out easily from the rear valve cover grommet and will allow some air to bypass the MAF sensor.
So just for the hell of it I put the car in accessory mode while checking something under the hood and I heard what sounds like a fuel injector clicking, key on, engine off. It sounds like the injector on the back side closest to the drivers side fender. I’m guessing that’s not normal and could that be causing the above mentioned problems?
disregard the ticking sound coming from the injector. I unplugged the idle air control valve and the ticking stopped. The car idles fine, why the hell would the iac be ticking like that with the engine off, key on in acc position?
In addition to the other suggestions, a few other things come to mind:
Check fuel pressure/volume.
If you have the ability to do so, check exhaust backpressure. A restricted exhaust would cause problems you described at higher RPMs because the engine can’t breathe.
If you feel surging at cruise, and have access to a scantool, check the O2 activity when cruising and at WOT. You should see ‘normal’ activity at cruise and it should be pegged rich at WOT. If that’s the case then your problem most likely isn’t fueling.
I’d also clean the MAF sensor and see if that makes a difference, though I would think that would act up more at lower RPMs, but worth a shot.
Sorry to keep adding problems here, but I started the car and did a wot when the engine sounded like it had a complete loss of power (didn’t even hit the rev limiter) I noticed arching from the one of the plug wires. I’ll try plugs and wires and go from there I guess
[quote=”cfyre0815″ post=31083]Sorry to keep adding problems here, but I started the car and did a wot when the engine sounded like it had a complete loss of power (didn’t even hit the rev limiter) I noticed arching from the one of the plug wires. I’ll try plugs and wires and go from there I guess[/quote]
I think Eric had a video on this subject – try a spray bottle with water and spray the wires/boots, etc.
If you have not yet found the problem to be with the wires and have access to a scan tool, please post the fuel trim numbers, mileage, last tune up and recent repairs. Is the check engine light on ?
In some cars the IAC valve retracts in preparation for a start up, it would replace a choke on a carburetor when engine is cold.Some of those 3.1 engines are also known for lower intake manifold issues also.
Did you check for coolant loss/burning or even checking for vacuum leaks?
More food for thought for you and keep us posted!
I actually bought the car 3 weeks ago with bad IM gaskets. It was leaking externally. I replaced those, everything with that is fine. Driving to work today, I hammered down on the accelerator and it took forever to get to 65. During that time the tach stayed around 4200 rpms. Like I said previously i think its misfiring under hard acceleration. Also when driving home last night i was locked on at 55 and going uphill slightly the rpms went from 1800 to 2500 bouncing around. Im gonna throw plugs and wires on and see what happens i guess
If you have known problems with the ignition wires start with those and then recheck for your symptoms.
Keep us posted.
So I’ve been out of town for a while and have not had time to take a look at the car for a while till yesterday. Anyways here’s the deal. Upon further inspection I found the misfire being caused be a fuel injector problem. After I replaced the intake manifold gaskets somehow when I put the injectors back in place I screwed up. The little black plastic piece that goes on the tip of the injector before the o-ring is missing. Is it possible to buy the replacement plastic piece I need? Worse case scenario I can get one from a salvage yard. Also I can hear a vacuum leak like sound under the plenum and I’m guessing its coming from that injector with that piece that’s missing. Finally when I pull the fuel rail again is there a way to prevent those black plastic things from falling down into the holes where the injectors go?
So I’ve been out of town for a while and have not had time to take a look at the car for a while till yesterday. Anyways here’s the deal. Upon further inspection I found the misfire being caused be a fuel injector problem. After I replaced the intake manifold gaskets somehow when I put the injectors back in place I screwed up. The little black plastic piece that goes on the tip of the injector before the o-ring is missing. Is it possible to buy the replacement plastic piece I need? Worse case scenario I can get one from a salvage yard. Also I can hear a vacuum leak like sound under the plenum and I’m guessing its coming from that injector with that piece that’s missing. Finally when I pull the fuel rail again is there a way to prevent those black plastic things from falling down into the holes where the injectors go?
hey man.
if you replaced plugs and wire’s and still having the same issue.
mabey the engine it running out fo rmp and power, and just not doing anything check fuel pressure and volume just to make sure that area is covered.
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