I need help.....my car used to miss when i accelerate in to the 3500-4500 rpm range....so i recently put 30lb fuel injectors to replace my 24 lbs..cause a guy i know suggested with my Elderbrock victor intake...the car would need bigger injectors than the 24's.but when i drove the car with the new injectors.... it was missing really bad..and idle wasnt level.so i took off my 75mm mass air meter and replaced it with the stock mass air meter....then changed the ignition module..and the car ran alot better...but if I get into throttle heavy the engine would start missing again.typically in low rpms like 1500-2000..but the funny thing is...if i barely give it throttle it won't miss....can anybody help me any suggestions...i'll really appreciate it....

 

have you changed your plugs or wires latley??

 

First off, you should know, maybe you do, but your MAF has to match the injector size. If you are putting your stock MAF back in, without a tune, you are not going to run right. 24's should be fine for what you have done anyway. Is your 75mm MAF calibrated to run 24's?

I would put the 24's back on, put your 75mm MAF back on, check you fuel PSI...should be about 40 to 42 without the vacuum on. Then I would check you plugs...look at the color and let us know. Also, recheck you gap, it should be .045 to .050. If you have it gapped to large, you will have a miss in higher RPMs.

 

ok I'll check the gap on the plugs...that seems to be only possibilty that i havent tried yet..so ur saying i gotta get a mass air meter that is made to go with 30 lb injectors???[&:]......because those 24lb aren't recommended with my intake.....but ill check my fuel pressure and the gap on the plugs..any other suggestions..?

 

Yes or get a tune.

And again, 24lb injectors will be fine till you get a MAF for the 30's. Who told you you needed 30's because of your intake?

 

this guy my father knows...said it....he specializes in mustang 5.0's...he owns a tune shop and builds race cars.

 

awful lot of head and intake for a stock block[&:]

 

Well below i put the stats on the Victor 5.0 intake i have: My father says it might be too big..what do yall think? i have a bbk 70mm throttle...its recommends a 75...i dunno.


Victor 5.0 (4000-7500 RPM)
Intended for 5.0L-based competition EFI engines and other modified 400 to 540+ HP engines, this aluminum EFI intake manifold is for non-emission racing applications and features shorter (11.5"), larger (50% more area) runners for power to 7500+ RPM. The air-gap base isolates manifold from hot oil and accepts stock/stock replacement fuel rails. Upper manifold clears tall valve covers and large fuel pressure regulators. 1994-95 Mustangs require conversion to 1987-93 inlet system. The Victor 5.0 manifold is designed to work with Edelbrock Victor Jr. #350-77179 or Victor #350-7721 cylinder heads. Fel-Pro Intake Gasket #375-1262 and an Edelbrock 75mm throttle body (for most applications) are recommended. Larger injectors may be needed depending on horsepower levels.

 

My 90 5.0 is doing the same thing. Low rpm miss/back fire . This is AFTER it was tunned. I have basicly everything this other car has. Please advise. The tunner said to check the plugs a wires. Re-placed all, same problem.

 

What is the correct MAF sensor for 30's? Size and brand? I have heard 75mm and 80mm. I have the Ford Motorsport one that they SAY is correct, but I'm starting to have my doubts now with a tune.