93 Volvo 240....on take off or when idling, when you give it gas it has a slight to very noticeable hesatation, if you move the pedal down slow sometimes it doesn't respond til 1/4 pedal, doesn't do it everytime but does have a miss, runs fine when driving at speed..you think fuel related (i.e. fuel filter or pump?)

 

Has the throttle body been cleaned lately?

 

no it has not....

 

I would try that first.
I have also seen a bad coil have similiar symptons as well.

 

Try checking for codes.

I have seen the MAF sensor cause this very problem.

The MAF sensor has a direct impact on the air/fuel mixture and the ignition timing, so it can cause all kinds of problems, and they often fail.

 

well thanks guys...No check engine light so checked codes, no codes either....then I checked and cleaned the throttle body (YUCK!) and also pulled the MAF sensor and cleaned it also, drives like a champ now thanks again

 

well a quick update, daughter drove it later on today a reported it still lunging forward, kind of like it hesitates then shoots forwards and takes off? Any other ideas...withhout some codes I'm in the "dark"

 

I still think it might be the coil and maybe even the computer.

 

okay last night my daughter said the engine light came on....can you look at it tomorrow morning...yeah at 6:15 before I go to work...well yeah I did and ran a diagnostic check...said MAF sensor...told her drive it and and I'll look at it when I get home...when I got home she said it was running bad...I checked connector and now it's reading O2 sensor....what do you think? change the O2 sensor???

 

What specific codes are you getting?

The O2 sensor and MAF sensor have a kind of "give and take" relationship. They both can have an effect on the other, so it can be hard to tell which is actually bad.

B

 

221 and 231

 

I would guess the MAF sensor is bad before the 02 sensor, with the codes and drivability issues you are having. I'd bet your thermostatic air flap in the air cleaner is stuck open to the heat stove pipe too. If you do replace the MAF, or anything else, make sure you pull the fuse for a minute to the ECM before starting the car.

B

 

well today it finally started doing something different, only at idle...it surges, I would say 2 to 3 hundred rpm up and down, until you put it in gear it will stop, but in neutral it will keep surging til you touch the gas....any clues, still has the 02 sensor code light lit

 

Throttle dirty?

 

the throttle body was dirty til I cleaned it...but it was real dirty, like I said it just started doing this and shows a O2 sensor code, any ideas on the idle valve, I believe that's what it's called, below the intake...could this part have anything relation to this problem?

 

Possiblelthe idle motor is bad.