trouble shoot this one.
 

i know this is a boat site, but this suburban is killing me. here's the deal. starts ok, revs ok in park, put it in drive and it falls on it's face coughs and sputters, if you barely give it gas it still misses but not as bad as when you nail it. here's what i've done so far. new plug wires, plugs, dist. cap ,rotor, fuel filter. any help out there?

it's a 88 suburban 454 tbi.
this problem just started and only is getting worse.
thanks
sly

I had a 93' that had a similer problem. I did all the same things you have done, and a little more. I finaly took it to the chevy dealer here in town and had them do a check on the systems. They replaced the injecters and most of the problem went away.

Cramer

Check fuel pressure, and clean injectors.

i thought of the injectors, but wouldn't it stumble in park too if i reved it up.
thanks
sly

This may sound crazy but when was the last time you put injector cleaner in it? Try double ar triple doseing it. It sounds to me like you have very dirty injectors. Pull the air cleaner off it and start it up then while you watch the stream of fuel coming off the bottom of the injector play with the throttle. Is the stream a fine spray or is it a lot of droplets? If it is droplets then do the heavy dose of injector cleaner...

tinkerboater
it's not fun to work on it when you get no where with it. besides i just want to get it running right so i can sell it. i just bought a new dodge RAM RIGHT
see ya
sly

It will only take 10 minutes to just go out and look at the spray pattern coming off the injectors. I'm preatty sure it is just dirty injectors. A friends truck of the same year had the same symptoms and the cleaner fixed it ( like new he said )

engine problems
 

I'm betting either clogged or worn out fuel pump in the tank or clogged fuel filter in the frame rail.

RPM a clogged fuel filter or bad fuel pump wont cause sputtering it will cause loss of top end power and the loss will slowly work its way down the rpm as the problem gets worse. With real dirty injectors the engine will idle fine in neutral and not in gear because in gear it is under a higher load and fuel atomization is more critical.

ok where do i spray the cleaner, it's tbi so the injectors spray down int the carb. both sides spray evenly and there is no loss of fuel supply when you gas it.
and yes i did replace the rail mounted fuel filter
tanks
sly