My automatic has a lot of miles on it, but it's been running lie a champ until recently. Whenever I get going right around 2500 to 3000 RPM the engine starts "chugging" for lack of a better description. The RPM go up and down by ~100, and the power seems to disappear.... then finally it engages and starts going. Even travelling at a consistent speed (~55-65) the enging chugs, and the RPMs flutter. I've replaced the plugs, and none of them were fouled, just dirty. The air filter is somewhat dirty, but doesn't seem clogged. I tried some of that fuel injector cleaner, and some gas additives, to no avail. I even tried an oil change for good luck. Is it the fuel filter? Fuel pump? Any suggestions?
Fuel pump sounds to be problem, though I'd replace air cleaner first to rule it out cheaper than pump (pump may have internal filters that are blocked)
SOURCE: temporary loss of power
have fuel pressure checked if ok should be approx 60psi.if ok try disconnecting mass air flow sensor connector to see if problem is eliminated. this the computer in to a default mode.the sensor is a common problem.thanks from schleck
SOURCE: 99 olds alero 2.4
I'm sure you have installed a fuel pressure gauge and monitored the fuel pressure while the problem is occurring?Another diagnostic tool which is easy to do,is while the problem is occurring,unplug one sensor at a time beginning with the Mass Air Flow first,.if it uses one.Many times,not always,depending on the sensor,if the sensor is taken out of the picture as far as what the PCM is seeing,like unplugging the MAF,the PCM will substitute the missing sensor output with a generic value that will allow the engine to at least run,and if unplugging for example the MAF,the engine idle speed returns to normal,you know you're onto the problem.You didn't mention if the engine ran ok other than the idle problem.As far as checking for vacuum leaks,i use something like brake cleaner or WD 40,more of a liquid,and it does sound like a vacuum leak.Plastic intake manifolds do develop nearly invisible cracks that open up more with heat.Revsisit the possibility.And as for the PCM,it is possible,but more likely a mechanical problem.Lastly,remove an O2 sensor or two before the catalytic convertor,run the engine and see if anything changes.Cheap way to verify the catalytic convertor is flowing and not restricting engine airflow,as i have seen bad cats cause misfire codes and strange problems.Good luck.
SOURCE: 1999 Silverado 5.3L hesitation ?
Filling it up with 92 octane will not help you so save your money to get other cool **** . If you want to put higher grade gas to the 89 ,but 87 will do the trick. Have you checked your pcv valve and hoses you might have a vaccum leak.
SOURCE: cannot get 1987 chevy van 20 to keep running... stalls out
Best do a fuel pressure test. Should have chg. fuel filter from the get go. The only other filter is on the end of the fuel pump in tank. Bad gas and dirty gas will plug up fuel filter, hense burn pump up.
SOURCE: My 1998 Dodge caravan started missing and chugging
Catalytic converter sounds plugged up. The popping back through the throttle body kind of gives me that suspicion. EGR valve stuck open could give that too, but I would think either one of these would throw a computer code.
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