98 qx4 jerking

[thatboiguy]

my 98 qx4 died about 3 weeks ago... but i took it to a mechanic who changed out the distributor, spark plugs, and wires. The fuel pump was changed about a year ago... The car ran fine for about a week, but it started jerking around 2000 rpms. It never stalled out though... i took it back to the mechanic and he could not find anything wrong with the diangnosis and suggested it might be the transmissions

any suggestions??? could it be one of the sensors from the sticky above??

[elwesso]

It could be the MAF... you could try getting a known good used one for not much money and see if it works... A lot of times thats what it does.

Does the car only do this in drive, or can you get it to "jerk" in neutral.. Rev it to 2000 in park and see what it does...

[thatboiguy]

only in drive

[elwesso]

If your trans fluid level is fine and shifts NORMAL it should be fine, i doubt the trans is to blame...

Without any other clues to whats happening, IE diagnostic codes or any other diagnosis, its hard for me to help.....

[thatboiguy]

check engine light is not on..... i'm thinking its a clog or something with the fuel line... i'm gonna switch out the fuel filter to see if it helps

i just found out that my brother put some fuel injector cleaner in the gas tank without completely filling up... maybe this was the cause of everything

[elwesso]

i kinda doubt it, that woudlnt cause this sort of problem... It would cause a sort of solid misfire.

just so we're on the same page, what the vehicle does is it sort of cuts on and off.. Like youll be driving and around 2000 RPM the car sorta bucks back and forth like someone is pushing the throttle on and off really fast...

[thatboiguy]

after i changed out the fuel filter, it got a little better, but it still jerks every now and then, mostly in the afternoons

... it feels more like the gas got cutoff for a sec. , then back on... it happens once or twice in a row and runs fine again.... its also worse when the a/c is on...

i'm out of ideas of what could be wrong

[boogar]

Mass air sensor

As they get hotter during driving, they will begin to fail.

Youll notice spitting , sputtering, and maybe some small muffeled back fires.

One major problem that can result from a bad MAS is the underside and exaust system starting on fire.

A bad MAS causes more fuel than is needed to be dumped into the maifold.

When this fuel doent get burned, and it pours thru the engine, choking it off.

If you keep pushing it, it will flood the exhaust sys with fuel and start a fire.

Be careful and good luck

[thatboiguy]

thanks for the advice... i'm gonna try switching it out......

just one more question.... should the service engine light be on if it is the MAF?

[thatboiguy]

great forum.... thanks again booger!!!!

the maf came in today via ups, switched it out and now the engine runs great