Having Trouble Need Suggestions

[C Davis]

Hey guys. First a little background: Red/Red 1990 #2874, nothing exotic, top end port and headers. For the last couple of days when I first crank the car it does fine for the first mile or so and then when leaving a red light or intersection it would "bog" when pulling off. I could engage the clutch and rev the engine and it would clear or once the rpm's got high enough it feels like the secondaries open and it would clear up with no more problems during the particular drive. Yesterday I left work, same deal, no problems at first, then stumbled, then cleared up, only this time 20 or 30 miles down the road in sixth gear and cruise set on 70 mph it started bogging and stumbling again. I managed to make it home by keeping the rpm's above 3500 or so but this time it hasn't gone away. It idles rough but will idle and tries to go dead when slowing down for a stop or turn. So far it hasn't thrown any codes, but I am borrowing a scanner from a fellow forum member this afternoon to see if it will tell me something. My initial thought was injectors, but I'm hoping someone has had similer issues that was just something simple. Sorry for the long winded run on question, and thanks in advance for any advice.

[GOLDCYLON]

Welcome to the forum. how many miles on your car? Initially its sounding like injectors but you knew that. No SES light right?

[C Davis]

54000 miles and no SES light.

[tomtom72]

A question, did you already change out the OEM fuel injectors?

:cheers:
Tom

[C Davis]

A question, did you already change out the OEM fuel injectors?

:cheers:
Tom

No, and that's my worry.

[tomtom72]

Okay, I hear you and with reading your symptoms I have to say I'm inclined to say that your OEM injectors have gone to injector heaven.

Your symptoms kind of match what mine did when they decided to retire. The car was fine, and then it wasn't. The hotter it got, the worse the miss. It got so bad that I could stand behind the car and smell the lean thru the exhaust on the right side....made my eyes tear at a hot idle!

There is a page in the 6E section, pp. 6E3-A-14, this is a print out of what all the scan data should look like on a normal motor, at idle in closed loop. That will be your template to compare your reading to. You would be interested in the fuel numbers and the O2 counts in particular the left and right Integrator #'s and the Block Learn Module left and right. Those readings will give you the low down on what the injectors are / or are not doing.

:cheers:
Tom

[QB93Z]

You might try checking your MAP sensor hose. If it gets softened by oil, it can collapse at high manifold vacuum, ie at idle. When the throttles are opened, the MAP doesn't see the manifold pressure change so the computer doesn't respond and the engine bogs on start from idle.

Jim

[C Davis]

You might try checking your MAP sensor hose. If it gets softened by oil, it can collapse at high manifold vacuum, ie at idle. When the throttles are opened, the MAP doesn't see the manifold pressure change so the computer doesn't respond and the engine bogs on start from idle.

Jim

I actually checked it as soon I got home because I've blown it off before. It wasn't unplugged but I hadn't thought about it collapsing. Thanks for the suggestion.:cheers: