Fuel Trouble?

pimpstang · 02-09-2005

I'm having trouble with my '98 GT. It hesitates/stumbles under hard acceleration. My plugs are new and plug wires are in good condition. I have a new fuel filter and clean injectors. I'm stumped. I thought it might by a fuel issue so I checked my fuel pressure and got 32 psi. at idle. (a little low) I don't know if the injectors are stock. The previous owner may have installed larger injectors causing the fuel pressure to drop, so what I'm asking is: Do I need a bigger fuel pump? and if so, what brand/size do I need? Thanks for the help.

TK421DS · 02-10-2005

I think your best answer is to take it to a shop and have it tested and looked at. There are many things involved in fuel problems.
TK

pimpstang · 02-10-2005

I really hate bringing my car to a shop. I know people that work in parts stores so I almost always do my own work. I've heard I should get it tuned, but I don't know where to do that. Would anywhere with a dyno be able to tune my car?

Mana4Real · 02-11-2005

Did you remember to disconnect the vacuum line before you took the reading?

pimpstang · 02-12-2005

I tried both....32 psi with the hose on, 40 with it disconnected. My Haynes book said to try both. I'll probably order a fuel pump just to be safe, but how big should I go?

Mana4Real · 02-12-2005

That's normal... You don't need a fuel pump. That's why I asked if you disconnected the vacuum line. Your fuel pressure is fine.

pimpstang · 02-12-2005

Thanks. That's a relief. But my car still stumbles when I run it hard, what should I do? I have noticed it only does this after warming up....if that means anything.

Glowmunkey · 02-12-2005

Quote:

Originally Posted by pimpstang

Thanks. That's a relief. But my car still stumbles when I run it hard, what should I do? I have noticed it only does this after warming up....if that means anything.

If you don't want to take it to a shop, you'll need some form of diagnostic equipment. Throwing parts at it is a really silly way to fix a problem...

Wideband O2 sensor, or use the stock narrow band O2 sensor, see what the voltage looks like when it stumbles. A scanner with a live data feed would make this task easier...

pimpstang · 02-13-2005

I appreciate the help. A thread on modulardepot.com said it may be ingition-related. I'll probably end up taking it somewhere around here to get it diagnosed because I don't have the equipment.