Hi, I've changed the the MAF sensor & cleaned the idle control valve, bit stumped as to what else it could be?

The car does sound as if its gotten slightly beefier (despite the opposite) could this be anything to do with the cat?

Any ideas?

 

Easiest way to check the MAF is to disconnect it. If it runs better then the MAF is faulty. Check for vacuum leaks, or blocked vacuum pipes. Also check battery connections are clean and tight.

Does it hesitate on acceleration, or all the time?

 

Could be a sticky throttle, faullty TPS, or a fueling problem.

 

Hi, yes everytime I accelerate the car hesitates, very sluggish!

 

In that case it's less likely to be the Throttle or the MAF.

Check for vacuum leaks and check battery connections and the ECM connections.

Could also be a fueling problem or the ECT sensor, injectors or the O2 sensor.

Does it have any fault codes stored?

 

Having the same or similar problem with my wifes focus, its been like this for a while, cant seem to get to the bottom of this annoying problem, idle is ok but occasionally erratic, when accelerating in neutral it will go steady to 2100 rpm, I keep slowly pushing down the pedal and the engine starts to hunt badly then after a bit more travel it clears and revs fine, if I floor it it hesitates, there also appears to be a real loss of power when driving and its quite thirsty too, checked the plugs, air filter etc, checked the map, tps, o2 (b1s1/s2) and all ok, checked the fuel pressure reg valve on the end of the fuel rail thas good, ive also checked for vac leaks as in the pipes I can see and they are good but I can hear what appears to be a vacuum leak near the throttle body/fuel pressure reg area but cant see or feel anything, any ideas anyone with this cos its doing my head in now

 

Spray some carb cleaner around the area whilst engine is running, if you spray it near a leak it will be sucked in and cause the revs to rise, thats the best way to confirm you have a vac leak and find it. Check those blanking plugs aren't cracked like mine were.

 

Compression check. Seen a few with burnt valves

 

Tried the old carb cleaner trick but still nothing and did think about a compression check, may do one now actually, but as it always starts ok unless its baking hot sometimes I didnt bother, beginning to wonder if the cat is partly blocked, tis a weird one, thx for the replies

 

vac pipes under the inlet common for splitting, 3 of them go into a T piece

 

Has it got the sensor between spark plugs 2 and 3 ? If so this monitors the temp in the cyl head etc if this is faulty it will also cause rough running and lack of power.

 

Had trouble with those last year and I replaced them, infact IIRC one had collapsed with the vacuum so they were replaced.

 

yes it has, I dont know what any meter readings would be so I cant test it but I guess its worth replacing, cant be that much so ill give that a go, checked the compression that seems to be fine, might do a leakdown test tomorrow just as a double check, I did unplug the map sensor as a just in case but it went into drastic hunt mode, it basically really replicated and magnified the problem 10 fold so plugged it back in and it returned to as it was, I think if the temp sender in the head dont do it then ill whip the inlet manifold off as a job lot, cos its a real pain to see anything

 

just be careful when fitting it as its easy to snap the plug off

 

Here you go:

 

Also worth pointing out I had convinced myself I didn't have a vac leak, but it turned out to be a vac leak in the end.

 

Hey thas brilliant, thx, will check that later, Im the other way round haha im convinced there is a vac leak but cant trace it, can hear it im sure but darned if I can find the bugger may end up smoking it out

 

Well although outside of those approximate figures It appears to be working, the cold reading is close enough, the hot reading is quite a bit different but the fault is there regardless of temperature or in open or closed loop, the only vac pipe I havent checked is the one down the back of the throttle body that goes to some sort of sensor associated with the aircon system, as I cant pinpoint a direct source for the said PITA suspected vac leak im beginning to think either the throttle body seal or the inlet manifold seal maybe, think its gonna have to come off

 

How would u smoke it out I tried carb cleaner as well for a leak but no luck is there something I can use

 

By using a smoke generator which connects and seals to the inlet via the induction pipe that comes off the air box, the smoke will fill the system and you will be able to see where it comes out if its leaking.

 

Ok thank u for ur help any other ideas would be great plz

 

Well after all this time im still non the wiser grrrr plus had other problems someone mentioned blanking plates or plugs where are these located, reluctant to remove the manifold just yet ... just welded the flexi joint back in the exhaust today after it busted off saved a few squid anyway, over 50 haha just used the old gaskets and its tight as a button but this ruddy manifold leak is such a pain

 

I had a simillar problem with mine, it would only working properly if i put my foot right down, when i backed off it would cut out, idle roughly, sometimes it wouldnt even start etc.

I spent the whole day with my brother looking for the problem, in my case it was a collapsed pipe.

you may have already checked it but find the breather box which is behind the exhaust manifold on engine, there is a pipe which comes off it at the top then runs over the gear box and into the inlet manifold.

where it goes into the manifold i found about 6 inhces back from the manifold the pipe had collapsed and closed it self off. probley from old oil and oil mist etc. Anyway i replaced the pipe with a new one and it started first time and ran like nothing was ever wrong with it.

it is hard to spot if the pipe has collapsed so you may have to feel the pipe to see if it has. hope this helps in some way.