whiterabit998

ok so on WOT this 94 gts rpm will climb, right until 4k and its like it hits a brick wall, it will climb so slooooww after that... it really weird, ive changed the plus, wires, rotor and cap and fuel filter.. idk wats the problem. the air filter is kinda dirty, but idk if that would be it.. the only thing i could think of is something might be wrong with the maf.. any help would be appreatiated

mjr46

try cleaning the maf and make sure the spout connector didn't fall out...ya' know the little plug you remove to set base timing..also you could try running a koeo/koer test and check for codes.......could check fuel pressure too

94StinkinLincoln

i hate that, i havent quite figured out why that happenes, i know retarted timing makes it slow, not enough FP can cause that, the rev limiter is at 5500 or 6250, it will bounce when it hits. running lean will make it do that, im willing to bet thats what it is. (make sure your balancer hasnt spun, when u set timing w/ spun balancer u timing will be off)

sultan68

my old 4 cylinder did that
sure was aggravating..it was so slow to begin with haha
anywho..my cats were clogged..i gutted them and it never did it again

whiterabit998

hmm ya i wanted to clean the maf, but wasn't sure with what. is carb cleaner ok?oh actually the guy before put in a msd box idk if he did it right.. and the cel will come and go as it pleases, i wish i could read it... but i only have an obd II reader.. this is for a friends gt ive owned only a 3.8 and 4.6, and im only 18!

1990lxhatch

I bet your exhaust is plugged. Your cats are probably melted down and causing a restriction. No spark advance would justmake it accelerate slower but it would still easily see 6250.

The 4.6 has a DPF EGR system which means it uses a pressure differential across an orifice to measure EGR flow. There is a tube coming off your exhaust manifold (I think it is the driver's side but it may be the passenger) and going to a strange looking vacuum valve (your EGR valve).Near the middle ofthis tube there will be two rubber hoses coming off small branches of this tube. In other words, the big tube has two small tubesnext to one another that branch off.There arerubber hoses coming off these smaller metal tubes thatconnect to a little square black sensor called the DPFE. You want to pull these rubber hoses off and connect a vacuum gauge to the larger of the two tubes. In neutral, rev your engine to WOT and let it reve as high as it can. If you see 3psi or more on the gauge (typically vacuum gauges will measure up to 5psi positive pressure) your cats are plugged.

Sounds more complicated than it is.Hard to type somethinglike this.But it is the easiest way for you to check for a restrictive exhaust - that I can assure you. Otherwise it's separate the exhaust at the manifolds or thread in a backpressure tester to the oxygen sensor ports.

OR. You could just say screw it and buy an off road H pipe and some three chamber flows

whiterabit998

hmm well this is on a five o, is it the same?

1990lxhatch

Shyt. I read too fast. I thought you had a 4.6 when you mentioned you previous cars, but if you have a 5.0 - the system is different and you don't have this luxury. Sorry, my mistake[:@]

tmajikman

run the koeo and koer test, the test can be done with a paper clip