I have a 89 5.0 and just got through rebuilding the engine. Its machined .030 over and I added a few upgrades in the process. I have some Ford Motorsport aluminum heads equivalent to GT40 heads. Changed to a Cobra intake, put a E303 cam in it. When I start it it runs but It runs rough and the timing is all over the place and even when I adjust it witha timing light It wont run on the 12 degrees I try to set it at. I do have the spout connector off when I adjust it. The vacuum is low at 5-8 inches at idle. It sometime will stall too. I try driving it and It is lacking in power and will stall when I come to a stop. I put it on a gas anylizer machine and it is running no CO at all. I called a Ford Motorsport engineer and he said I need Ford motorsport intake gaskets instead of the Felpro I was using and the Roller rockers instead of the stock ones. I have changed those out and still runs the same. I checked fuel pressure And its 42psi in spec. I have checked TDC with a piston stop to make sure the timing marks are correct and it checks good. I ran out of ideas any one have more for me to check? Thanks Terry

 

well as for needing the fms gaskets...that's horse shiz!! fel pro lower will work fine and equivilant to a cobra or gt-40 with the round holes will work fine as long as it all lines up...first thing I'd do is run a koer test and look for codes..if none exist second thing I'd do with low vaccumis look for a vaccum leak.....if you have access to a smoke machine.. that'd make life simple

 

Thanks for the reply I figured he was trying to sell me his product. I did a KOER with a NGS and found no codes. I will grab the smoke machine from work and try that. I did find a article on another forum about intake manifolds particular to the GT40 and Cobra intakes. The one that say Made in China are bad. I looked under mine and it does say that. I bought it through Summit. I looked at a stock Cobra manifold today and compared to mine the mounting flange size is much smaller on mine. That may be the problem. I hope the smoke machine will verify this. Thanks Terry

 

GOOD!!!!!! YOU HAVE ACCESS to a smoke machine and the NGS WOW i'M IMPRESSED.......most don't thumbs up to you which will make diagnosis hopefully quicker

 

It Helps when you work at a garage with mostly fords in it. Ford police cars that is. I will let you know what I find.

 

cool!! good luck!!

 

just had this issue,


your prob 180 * off, it will run (almost normal) but no power.

setting it to 12, with the light connected to the passenger side cylinder, the very first one up front.

 

I thought it was that at first so for kicks I turned it 180 and it was worse. I fugured out that the intake is not sealing to the heads. I have tried several name brand intake gaskets and it wont seal. I found some redesigned Felpro gaskets today and will give those a try for the 3rd time. I have read on another mustang forum that the Cobra intake I have is a off brand of the real cobra intake and they are junk. I may be finding another intake.

 

what is your ..whole build so we can possible reccommend an intake.....so the smoke test worked??

 

try taking your distributor one gear off and see how it run. dont ask why but for some stangs it would make that much of a differance.