Why is my sierra cosworth spluttering at 135MPH?

Question:
its fine every where else its just in fifth gear at 4500-5000rpm

Answers:

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get the thing on a rolling road with a diagnostic hook-up. this will give you a full report of what is wrong. any good tuning shop will then be able to rectify the problem and or give you options to increase performance. personally iot sounds like an ecu mapping problem where the engine may be leaning out at higher speed. good luck..

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Fuel pump is a little weak and not keeping up with the need for fuel.

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135 mph bloo dy he ll thats not bad for an old banger?

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so 90's............just messing wot a cool car........sorry don't know much bout engines...........

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Yeah ...right !!

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Possibly because you're not actually supposed to drive at 135mph on British roads? It's the car's way of telling you to slow down, love!

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Hi - sorry not an answer to this question ... though 135mph is a bit fast, lol.

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It's about the Bulldogs ... why not also try the Champdogs site - I've limited the available puppies by region & came up with three breeders based in the Midlands (not sure where because they didn't say on their Kennel Page - though the Kennel Page does contain contact information) - if you weren't happy with the results on ePupz then you might like to take a look:

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http://www.champdogs.co.uk/guided/all_bu...

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mmmmmmmmmm fast chick

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cos it's gonna break up..you should'nt be goin that fast in an old bucket like that.they were a nice motor a while back , but please consider other drivers who have newer motors than yours whose brakes are twice as effective as yours , then when you smash into the back of em doin 135 and split them into atoms and also yourself...is it worth it ?

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slow down asshole
or kill yourself

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check your fuel filter ,if its dirty it could be preventing your fuel pump from pressurizing the system properly at that rpm range,and it could be that maybe your clutch is slipping too ,take it in for a diagnostic.

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It might be pumping to much gas into the intake

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No enough detail, If Boost is low check all intake hoses ant air filter, but is more like to be ignition, it rev fru problem at lower sped but work hart at 4500 is peak torque, fit new plugs for starts.
If it had bigger turbo perhaps ignitio n need re map.

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135 mph is slow Hammond crash at 300 plus just get hed ake.

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your hitting the rev limiter

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it mgiht have something to do with whats called a speed limiter or rev limiter. basicly what that does is it doesnt allow the car to go over a certaint speed. a rev limiter doenst allow the car's engine to go above a certaint RPM level. your brother may have found a way to disable this limiter. usualy they come pre-set.

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check the fuel pump,also check if the fuel sensors on the cat are working,check if the inlet manifold gasket is not torn,have the spark plugs been changed and are the correct heat range,have the ign leads checked,has the timeing belt jumped

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135mph is a bit gay for a cossy ! sounds like needs a service. ignor the other idiots.. u didnt say u were driving it on a public road

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illegal why would you want to?

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Get it on a rolling road and compare to your brothers if you can.

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Have you had a compression test done?

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[edit] Another thought: is there any difference in wheel sizes between yours and your brothers?

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you need to have the cpu tuned to advance timeing at those speeds