TPS Problem?

[Benwell]

My 1.7 Puma engine has been acting funny for quite a while. I think I may know what it might be but I wanted an opinion from you guys if you had any idea.

Basically I used notice it more a higher speeds but now i'm beginning to notice it at various speeds. I'll be on the motorway doing a steady 80 say for example. My foot will not move but all of a sudden my speed and revs will slowly drop 5/6mph and then without me doing anything surge right back up again to 80. As though i've taken my foot off the gas and then floored it back to 80 again lol. It's been happening for months, but i'm starting to notice it across right at all speeds.

I used to think I had a faulty lambda (which I haven't yet looked into further) and it was fuelling problem, but yesterday I thought maybe it could be an intermitent problem with the throttle position sensor?!

I'll put it under a diagnostics test as a last resort, but I thought i'd ask first and see if anyone had experienced it before.

Oh and i've already replaced the MAF before anyone suggests that

Any help greatly appreciated!

 

[yippeekiay]

Your not going up and down hills by any chance - I know, stupid question but I've had people ask me that sort of question before and they then do a second take and say 'oh yeah, didn't think it would make much difference'....lol.

 

[Benwell]

No, it's defiantely a much more noticeable drop in power than a change in gradient.

I first noticed it on the motorway, the best way to describe it is like someone applying the brakes very slightly or pulling the handbrakes. It lasts a few seconds and then my speed shoots back up to were it should be. It's the weirdest thing ever and it's getting worse by the week.

I'm guessing its either:

Coilpack
TPS
Lambda
or somekind of low voltage problem.

Just wandered whether it's a common problem with the Puma engines.

 

[mrMechanix]

If it were the coilpack you would feel a misfire and the car would run rough. Lambda sensor is a real possibility or coolant temp sensor. Could be a fuel pump or filter problem. choked filter can give these symptoms, if its not been changed in a while i'd try that first. cheapest and easiest. besides its good to change it once a year anyway. hope this helps.

 

[Benwell]

Thanks for your reply!

It has been suggested that it could be a fuel filter problem, definatly worth a try. Thanks!

 

[ScubaSteve]

doubt it

i would say maf or lambda

 

[crystalpuma]

I have a similar problem, well along same lines anyway - at low revs e.g. when pulling away from junctions, the car hesitates, bit like turbo lag or very very bad engine labour as if revs too low, but it is too bad to just be that and happens when I know the engine shouldn't be labouring. Fuel filter is only about 2 years old, can it have blocked already, or what else is likely?

Sorry if that makes no sense, I didn't sleep last night and it shows!

 

[JiiHu]

crystalpuma: Did you find any solution to your problem?