Bad Hesitation Problems

Well, if anyone recalls, i was having troubles with erratic idle. Anywho, here goes. Changed my gastank and ended up plugging a fuel filter 30 mi. from home, so i drove it home with the plugged filter. Carboned up the Idle air ctrl valve, so i took that off and cleaned it up good, and that solved my funky idle. However, the bronco now has troubles with a bad hesitation. Figured I may have plugged another filter, so it put a new one on. Now, the hesitation is only under load and at any engine temperature (cold or up to operating temp) and it will rev up fine in neutral or park. The truck is a 1990 5.0L (no mods) with a rottenmatic. New tank, old pump, new fuel filter, no luck. Any Ideas what could be wrong? Another bad sensor? Something else in need of cleaning? I'm lost as to what the problems could be. I think i read in another topic something about the Intake Air Temp sensor causing a hesitation, but I don't know much about that, let alone where its located and how to test it etc. Any help is greatly appreciated, thanks. Oh yeah, and there aren't any codes being thrown at me. Thanks again.

start with the basics,check pump pressure,timing,tune it up

I always start with the simple stuff first what about injectors?they don't always show up as an idiot light.if your computer light isn't on it doesn't mean nothing is wrong.

BUY A BOOK ON YOUR TRUCK learn everything you can about it.the book will teach you test parts yourself.

there is nothing wrong with automatics

Well, i don't want to spend any more than i have to, i'm going to be selling it once i get this little problem worked out. I don't have anything against automatics, its just not my tranny of choice. I like the direct feeling and feedback that a standard trans gives.

giving up huh?

Yeah, gave up saturday and put my firebird back on the road. After 4 fuel filters and 2 weeks worth of smelling like gas, i am about to wits and wallets end with this money pit. It's been nothing but a PITA since i got it. Anyways...It still hesitates...

you might want to try the throttle position sensor or mass airflow sensor. those both control mixture and it sounds like your running rich on your truck.

Well, the bronco doesn't have a mass air sensor, at least there isn't one mounted externally on the intake tubes, i've never seen or known one to be mounted inside the intake itself, but yes, it def. seems to be running rich.

it basically comes down to the engine thinking that its getting more air than it actually is. my best guess is throttle position sensor. A chiltons book is well worth the money!!

If only i could find a chiltons in this area...the only thing avail. is a Haynes. I did have my IACV off, i wonder if i hadn't take it back off and then grease up the gasket...maybe a leak there...*shrug*

I had to order my Chiltons off of Ebay. Got it used for $10 bucks though. I think you can order them through amazon too.

I think NAPA might carry Chiltons that is the only place in this area other then the library that I have seen them

Have you ever had a 2 stage fuel injection cleaning done? What it does is first a cleaner is put in the fuel tank then the second stage is another cleaner feed through the vacuum line cleaning everything in the top end. I don't like to do this but "Jiffy **** b-( " can do this for you for around $70. If you go there tell them you only want the fuel injection cleaning NOTHING ELSE!

I used to work for them and quit because they scammed there customers. :angry:

try cleaning around the butterfly valve in the throttle body , it will only

cost you a can of throttle body cleaner and 20 minutes. use an old toothbrush

to help clean where the valve seats.